Male Larynges Research Articles

Survival trends in European cancer patients diagnosed from 1988 to 1999

We analysed data from 49 cancer registries in 18 European countries over the period 1988–1999 to delineate time trends in cancer survival. Survival increased in Europe over the study period for all cancer sites that were considered. There were major survival increases in 5 year age-adjusted relative survival for prostate (from 58% to 79%), colon and rectum (from 48% to 54% men and women), and breast (from 74% to 83%). Improvements were also significant for stomach (from 22% to 24%), male larynx (from 62% to 64%), skin melanoma (from 78% to 83%), Hodgkin disease (from 77% to 83%), non-Hodgkin lymphoma (from 49% to 56%), leukaemias (from 37% to 42%), and for all cancers combined (from 34% to 39% in men, and from 52% to 59% in women). Survival did not change significantly for female larynx, lung, cervix or ovary. The largest increases in survival typically occurred in countries with the lowest survival, and contributed to the overall reduction of survival disparities across Europe over the study period. Differences in the extent of PSA testing and mammographic screening, and increasing use of colonscopy and faecal blood testing together with improving cancer care are probably the major underlying reasons for the improvements in survival for cancers of prostate, breast, colon and rectum. The marked survival improvements in countries with poor survival may indicate that these countries have made efforts to adopt the new diagnostic procedures and the standardised therapeutic protocols in use in more affluent countries.

Human papillomavirus vaccination: stabbing in the dark?

In September, the human papillomavirus (HPV) vaccine will become part of the UK’s immunisation programme. Initially, 12–13-year-old girls and a catch-up group of 17–18-year-old girls will be targeted in schools, with a three-dose vaccination schedule at 0, 1, and 6 months. Cervarix, a bivalent vaccine developed by GlaxoSmithKline, has been chosen in favour of Merck’s quadrivalent Gardasil. This vaccination programme could prevent 70–80% of cases of cervical cancer and over 90% of cases of genital warts, but its potential success depends on uptake. In a pilot study of just over 2800 schoolgirls in Manchester aged 12–13 years, overall uptake was 71% for the fi rst dose and 69% for the second. Uptake was lower among girls from less affl uent backgrounds and minority groups, and results from the third dose were not reported. Cancer Research UK reports these results as “encouraging”, but higher uptake would be desirable, particularly as cost-eff ectiveness models assume uptake greater than 80%. There are many possible explanations for poor uptake: fi rst, the logistical diffi culty of administering three doses of vaccine at specifi c times. Second, fears of the girls, their parents, and perhaps even teachers that the vaccination is dangerous. Third, concerns on moral or religious grounds that use of the HPV vaccine will promote sexual promiscuity. Fourth, girls, parents, and teachers lacking awareness of the advantages of immunity to HPV. Awareness is necessary for informed consent, which is a prerequisite for vaccination. However, a recent study reported that only 23% of 1348 Italian 14–24-year-old women knew that HPV can infect genital mucosa and had heard about cervical cancer. If these results can be extrapolated, it is worrying that most girls being off ered vaccination against HPV might have no concept of what the virus does, and certainly therefore no understanding of the benefi ts of immunity. If the programme is extended to include boys, conveying the value of herd immunity will be an even greater challenge than promoting individual immunity. Raising awareness of the link between HPV and cancer of the male genital tract, oral cavity, oropharynx, and larynx may be a more successful route for encouraging vaccination. The Department of Health has planned an advertising campaign, directed at young girls and their parents, to coincide with the fi rst injections. Hopefully, the multimedia messages will illuminate all those who are in the dark about the benefi ts of vaccination.

Mobile larynx in Mongolian gazelle: Retraction of the larynx during rutting barks in male Mongolian gazelle (Procapra gutturosa Pallas, 1777)

This study provides the first evidence of pronounced temporary laryngeal descent in a bovid species. An elaborate acoustic display is prominent in male courtship behavior of polygynous Mongolian gazelle. During rut, rounding up of females is accompanied by continuous head-up barking by dominant males. Throughout the rut their evolutionarily enlarged larynx descends to a low mid-neck resting position. In the course of each bark the larynx is additionally retracted toward the sternum by 30% of the resting vocal tract length. A geometric model of active larynx movements was constructed by combining results of video documentation, dissection, skeletonization, and behavioral observation. The considerable distance between resting position and maximal laryngeal descent suggests a backward tilting of the hyoid apparatus and an extension of the thyrohyoid connection during the retraction phase. Return to the resting position is effected by strap muscles and by the elastic recoil of the pharynx and the thyrohyoid connection. An intrapharyngeal inflation of the peculiar palatinal pharyngeal pouch of adult males is inferred from a short-time expansion of the ventral neck region rostral to the laryngeal prominence. The neck of adult dominant males is accentuated by long gray guard hairs during the rut. The passive swinging of the heavy larynx of adult males during locomotion gives the impression of a handicap imposed on rutting males. Apparently, this disadvantage becomes outweighed by the profits for reproductive success.

Sexually differentiated, androgen-regulated, larynx-specific myosin heavy-chain isoforms in Xenopus tropicalis; comparison to Xenopus laevis

We have shown that the sarcoplasmic myosin heavy-chain (MyHC) isoform xtMyHC-101d is highly and specifically expressed in the larynx of the aquatic anuran, Xenopus tropicalis. In male larynges, the predominant MyHC isoform is xtMyHC-101d, while in females, another isoform, xtMyHC-270c, predominates. The X. tropicalis genome has been sequenced in its entirety, and xtMyHC-101d is part of a specific array of xtMyHC genes expressed otherwise in embryonic muscles (Nasipak and Kelley, Dev Genes Evol, in press, 2008). The administration of the androgen dihydrotestosterone increases the expression of xtMyHC-101d in juvenile larynges of both sexes. Using ATPase histochemistry, we found that in adults, X. tropicalis male laryngeal muscle contains only fast-twitch fibers, while the female laryngeal muscle contains a mix of fast- and slow-twitch fibers. Juvenile larynges are female-like in fiber type composition (44% slow twitch, 56% fast twitch); androgen treatment increases the percentage of fast-twitch fibers to 86%. xtMyHC-101d predominates in larynges of dihydrotestosterone-treated juveniles but not in larynges of untreated juveniles. We compared the larynx-specific expression of xtMyHC genes in X. tropicalis to the MyHC gene expressed in X. laevis larynx (xlMyHC-LM) by sequencing the entire xlMyHC-LM gene. The androgen-regulated xtMyHC that predominates in the male larynx of X. tropicalis is not the gene phylogenetically most similar to xlMyHC-LM at the nucleotide level but is instead a similar isoform found in the same MyHC array and expressed in the embryonic muscle.

Report on trends of incidence (1970–2002) of and mortality (1952–2002) from cancer in Germany

The paper presents the statistical analysis of current and past trends of cancer mortality rates in Germany in terms of annual percent change, overall and for the major sites, and contrasts them with trends in incidence of the Cancer Registry of the Saarland, the only registry in this country with long-term completeness. It addresses also the issue of a cross-over of cancer mortality and mortality from cardiovascular diseases (CVD) in the near future, as suggested by various authors. Analyses are based on the mortality data of the official mortality statistics as published by the Federal Statistical Office and reported annually to the WHO, and the regularly reported incidence data of the Cancer Registry of the Saarland. The data was age-standardised and analysed by piecewise regression using a freely available dedicated software package. The report shows a downward trend of mortality rates for all cancers combined based on declining rates for many individual sites with only few exceptions affecting mainly females (e.g. lung cancer). Recently, the long-term increase of cancer incidence also flattened out with rather heterogeneous underlying site-specific trends increasing for some sites (e.g. cancers of the intestine, breast, prostate, or some lymphoma) and decreasing for others (e.g. cancers of the stomach, gall bladder in females, larynx, and lung in males). A crossover of cancer mortality and mortality from CVD might occur-if at all-after 2,020 in males and 2,030 in females. Depending on cancer site, primary prevention (e.g. lung cancer among males), early detection (cervical cancer), and treatment (e.g. breast and testicular cancer, lymphoma) contributed to the current decline of mortality rates. Absence of a turnaround (e.g. lung cancer among females), slower decline than in other countries (e.g. cervical cancer), or later turnaround (e.g. breast cancer) may be related to failures in promoting prevention (lung cancer among females), early detection programmes (cervical cancer), or delays in the translation of modern treatment into routine health care (breast cancer) and indicate major challenges for current and future health policy.

Collective spectral pattern complexity analysis of voicing in normal males and larynx cancer patients following radiotherapy

Normal male voicing is defined, and voicing recovery after radiotherapy for larynx cancer quantified, using spectral domain complexity analysis of electro-glottogram conductance variations measured across the larynx during vowel phonation. These variations directly correlate with vocal fold vibrations that drive voice production. Approximate entropy is shown to concisely quantify the collective spectral pattern of the sustained impedance waveform after normalisation with respect to the varying fundamental frequency and power. It reveals a double banded reference standard in normal males. Forty-eight male larynx cancer patients were studied in parallel with an unrestricted perceptual analysis before and 1 year after radiotherapy. Two-thirds of patients had spectral approximate entropy values close to normal approximate entropy reference standards after 1 year. A quarter of patients showed reduced approximate entropy, predominantly in the most aberrant perceptual categories. Collective spectral pattern complexity analysis of vowel phonation has the potential to be a reliable, single parameter measure of voicing quality in these cancer patients.

Laser projection in high-speed glottography for high-precision measurements of laryngeal dimensions and dynamics

The detection of metric dimensions of laryngeal structures yields valuable information for both clinical and research purposes. The use of a laser projection system combined with a high-speed camera system enables the derivation of absolute spatial dimensions of the larynx. Vocal fold length, vibratory amplitudes and velocity can be derived. This was shown on 13 female and 9 male larynges during phonation of a vowel at different pitches. The vocal fold length, the amplitude of oscillation and the velocity of vibration were analyzed in between pitches of 119 to 236 Hz in the male group and 181 to 555 Hz in the female group. The vocal folds' length ranged from 8.4 to 14.3 mm in the male group and from 7.7 to 15.6 mm in the female group. Corresponding amplitudes varied from 0.33 to 1.24 mm (male) and from 0.38 to 0.82 mm (female). The maximal velocity of vibration was between 0.48 and 0.85 m/s in males and between 0.47 and 1.3 m/s in females without showing significant correlation between each parameter. The described technique enables the detection of absolute spatial laryngeal dimensions of female and male subjects at different pitches. Dynamic processes such as velocity of vibration can be quantified. The detection of metric data serves to optimize biomechanical model computations and provides valuable information in diagnostics and interpretation of organic and non-organic voice disorders.

Spectral pattern complexity analysis and the quantification of voice normality in healthy and radiotherapy patient groups

Vocal fold functionality may alter in response to direct radiotherapy or indirectly by perturbation of the hypothalamic–pituitary axis. Perceptual assessment of voice quality is difficult to summarise in a single, reliable figure of normality and normality itself is undefined. In this study spectral analysis of vocal fold vibration, based on impedance variations measured across the larynx using an electro-glottogram, is used to build a single parameter description of standard vowel phonation in the normal male population. Patient data and perceptual assessment are then compared to this standard. The spectral pattern of the vowel/i/ electro-glottogram time series is analysed using approximate entropy after dynamic fundamental-harmonic frequency normalisation. The approximate entropy provides a single estimate of the spectral pattern complexity. A cohort of 89 normal males formed two statistically distinct groups, G1, with strong spectral pattern and high complexity 0.338 (±0.036), and G2 with a weak spectral pattern and low complexity 0.175 (±0.049). Membership ratio G1:G2 was 2:1. A cohort of 30 male larynx cancer cases were analysed approximately 3–6 months after irradiation, and three male prophylactic cranial irradiation cases some years after treatment. Two-thirds of patients had G2 or lower levels of complexity. The lower G2 complexity level appears to be the subjective, as well as the objective, threshold for voice normality.

Estudo histológico da ossificação da cartilagem tireóidea

Com o passar da idade, ocorrem progressivamente ossificação e formação de medula óssea nas cartilagens laríngeas. O conhecimento dessas modificações é importante para a diferenciação com invasão por câncer. OBJETIVO: Avaliar comparativamente as porções cranial e caudal da cartilagem tireóidea quanto a alterações histológicas em indivíduos adultos do sexo masculino, observando a ossificação e a formação de medula óssea. FORMA DE ESTUDO: Experimental. MATERIAL E MÉTODO: Foram estudadas 7 laringes obtidas de cadáveres do sexo masculino submetidos a exame necrológico no Posto Médico-Legal de Santos, da Polícia Civil do Estado de São Paulo. A idade variou de 39 a 60 anos, com mediana de 53. Não se teve acesso à informação de hábito de tabagismo e etilismo. Os espécimes foram descalcificados e corados pela hematoxilina-eosina. A ossificação foi estudada pelo método histométrico baseado na estereologia e a presença de medula óssea foi realizada de forma qualitativa (presença ou ausência). RESULTADOS: Nos segmentos craniais, notamos uma média de 42,8% de ossificação e a presença de medula óssea em 57,1%. Nos segmentos caudais, a média de ossificação foi de 72,8%, com medula óssea em 87,5%. CONCLUSÃO: A ossificação da cartilagem tireóidea e a formação de medula óssea são mais intensas e precoces na sua topografia cranial.

Sexual Dimorphism of the Larynx of the Mongolian Gazelle ( Procapra gutturosa Pallas, 1777) (Mammalia, Artiodactyla, Bovidae)

The larynges (except for the epiglottis) of two adult Mongolian gazelles, one male and one female, were dissected. This species is characterized by a pronounced sexual dimorphism of the larynx. Dimorphism with regard to the size of the entire larynx and of the thyroid cartilage is about 2:1 whereas the difference of mean body mass is about 1.3:1 between males and females. Unexpectedly, and in contrast to other bovids, the larynx of the male Mongolian gazelle has a paired lateral laryngeal ventricle. However, in contrast to horse, dog, pig and many primate species also possessing such a paired ventricle, its rostral opening in the Mongolian gazelle is situated lateral to the corniculate process of the arytenoid cartilage. The neck of the laryngeal ventricle is embraced by the bifurcated cuneiform process of the epiglottis. Despite the enlarged laryngeal cartilages, the vocal process of the male arytenoid cartilage is relatively shorter than that of the female. The male thyroarytenoid muscle is clearly separated into a rostral ventricular muscle and a caudal vocal muscle whereas the female's, as in other bovids, is almost uniform. The lateral sac of the two-chambered laryngeal ventricle in the male projects laterally between the ventricular and the vocal muscle. As in the domestic bovids and in many other artiodactyls the larynx of the male Mongolian gazelle is lacking any rostrally directed membraneous portion of the vocal fold. Instead, the thick and tough bow-like vocal fold projects caudally into the infraglottic cavity and is supported by a peculiar pan-like fibroelastic pad. This resilient element, situated medial to the bipartite thyroarytenoid muscle, might be a homologue of the vocal ligament, eventually including lateral portions of the elastic cone. A fibroelastic pad is absent in the female. The resilient floor of the laryngeal vestibulum, ventral to the fibroelastic pad, is rostrally and caudally subducted by tube-like spaces. Evolutionary enlargement of the male larynx, including the vocal folds, and of the caudal portions of the vocal tract may have shifted the fundamental and formant frequencies to a lower register. The paired lateral laryngeal ventricle might produce an amplitude increase of the vocalizations assisted by differential action of the bipartite thyroarytenoid muscle. In addition, the peculiar shape, size and tough consistency of the male vocal folds may, as in roaring felids, assist in producing high amplitude and low frequency vocalizations. Perhaps the biological role of the enlarged male larynx of Procapra gutturosa has evolved in relation to its mating system. In the rutting season, dominant males establish individual territories and maintain harems. During prolonged courtship prior to mating, these males perform an acoustic display uttering loud and guttural bellows. In addition, the bulging ventral neck region of males may serve as an optical attractant for the females. Thus, the evolution of the enlarged larynx of the male Mongolian gazelle may have been favoured by sexual selection.

Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses.

Atrazine is the most commonly used herbicide in the U.S. and probably the world. It can be present at several parts per million in agricultural runoff and can reach 40 parts per billion (ppb) in precipitation. We examined the effects of atrazine on sexual development in African clawed frogs (Xenopus laevis). Larvae were exposed to atrazine (0.01-200 ppb) by immersion throughout larval development, and we examined gonadal histology and laryngeal size at metamorphosis. Atrazine (> or =0.1 ppb) induced hermaphroditism and demasculinized the larynges of exposed males (> or =1.0 ppb). In addition, we examined plasma testosterone levels in sexually mature males. Male X. laevis suffered a 10-fold decrease in testosterone levels when exposed to 25 ppb atrazine. We hypothesize that atrazine induces aromatase and promotes the conversion of testosterone to estrogen. This disruption in steroidogenesis likely explains the demasculinization of the male larynx and the production of hermaphrodites. The effective levels reported in the current study are realistic exposures that suggest that other amphibian species exposed to atrazine in the wild could be at risk of impaired sexual development. This widespread compound and other environmental endocrine disruptors may be a factor in global amphibian declines.

The descended larynx is not uniquely human.

Morphological modifications of vocal anatomy are widespread among vertebrates, and the investigation of the physiological mechanisms and adaptive functions of such variants is an important focus of research into the evolution of communication. The "descended larynx" of adult humans has traditionally been considered unique to our species, representing an adaptation for articulate speech, and debate concerning the position of the larynx in extinct hominids assumes that a lowered larynx is diagnostic of speech and language. Here, we use bioacoustic analyses of vocalizing animals, together with anatomical analyses of functional morphology, to document descended larynges in red and fallow deer. The resting position of the larynx in males of these species is similar to that in humans, and, during roaring, red-deer stags lower the larynx even further, to the sternum. These findings indicate that laryngeal descent is not uniquely human and has evolved at least twice in independent lineages. We suggest that laryngeal descent serves to elongate the vocal tract, allowing callers to exaggerate their perceived body size by decreasing vocal-tract resonant frequencies. Vocal-tract elongation is common in birds and is probably present in additional mammals. Size exaggeration provides a non-linguistic alternative hypothesis for the descent of the larynx in human evolution.

Changes in length and spatial orientation of the vocal fold with arytenoid adduction in cadaver larynges.

Videoendoscopy suggests that arytenoid adduction (AA) surgery not only medializes the paralyzed vocal fold, but increases the length of its membranous portion so that it more closely resembles the normal side. This could represent either real length change or out-of-plane rotation. Computed tomography scanning was performed on adult male cadaver larynges before and after the AA procedure to measure changes in length and spatial orientation of the vocal fold. Three-dimensional coordinates of radiopaque markers on the anterior commissure, posterior glottic midline, and vocal processes were determined. The distance between the vocal processes was 3.9 mm before, and 0.8 mm after AA. The mean vocal fold length was 12.4 mm before, and 13.4 mm after AA (p = .14). The vocal process moved consistently caudally, an average of 3.5 mm (p = .02). The data suggest that clinically apparent vocal fold length changes with AA could be an illusion due to vertical displacement of the vocal process, and not actual lengthening.

Cancer mortality in Indian and British ethnic immigrants from the Indian subcontinent to England and Wales.

Risk of cancer mortality from 1973 to 1985 in persons born in the Indian subcontinent who migrated to England and Wales was analysed by ethnicity, and compared with cancer mortality in the England and Wales native population, using data from England and Wales death certificates. There were substantial highly significant raised risks in Indian ethnic migrants for cancers of the mouth and pharynx, gall bladder, and liver in each sex, larynx and thyroid in males, and oesophagus in females. There were also substantial raised risks in these migrants of each sex for non-Hodgkin's lymphoma and myeloma. For the mouth and pharynx, and liver in each sex, and gall bladder in females, there were also raised risks of lesser magnitude in British ethnic migrants. For colon and rectal cancer and cutaneous melanoma in each sex, ovarian cancer in women and bladder cancer in men, there were appreciable significantly reduced risks in the Indian ethnic migrants not shared by those of British ethnicity. Appreciable raised risks in British ethnic migrants not shared by those of Indian ethnicity occurred for nasopharyngeal cancer in males, soft tissue malignancy in both sexes and non-melanoma skin cancer in males. In migrants of both ethnicities there were appreciable significantly raised risks in each sex for leukaemia and decreased risks in each sex for gastric cancer, for lung cancer except in females of British ethnicity and in males for testicular cancer. The results suggest the need for public health measures to combat the high risks of oral and pharyngeal cancers and liver cancer in the Indian ethnic immigrant population of England and Wales, by prevention of betel quid chewing and hepatitis transmission respectively. The data also imply that early exposures or early acquired behaviours in India, or exposures during migration, may increase the risk of leukaemia and reduce the risks of gastric and testicular cancers in the migrants irrespective of their ethnicity. Aetiological studies would be worthwhile to investigate the reasons for the sizeable decreased risk of colon and rectal cancer and increased risk of gall bladder cancer in each sex and the increased risk of thyroid and laryngeal cancer in males and oesophageal cancer in females of Indian ethnicity but not of British ethnicity who have migrated from the Indian subcontinent.

90: Subglottic Spread of Glottic Carcinoma: The Significance of Laryngeal Size as Related to Gender

Objective: Although it is accepted that there are size differences between female and male larynges, criteria for conservation laryngeal surgery for glottic carcinoma have not specifically addressed this matter. A laryngeal cadaveric anatomic study was undertaken to determine if the current criteria for conservation laryngeal surgery for glottic carcinoma is uniformly applicable to the female larynx. The past several decades have seen an increase in tobacco use among women, accompanied by an increased incidence of laryngeal cancer, thus underlying the relevance of a study of this nature Methods: Anterior midline measurements between key landmarks of the larynges of 10 female and seven male cadavers were carried out and assessed. These measurements included the following: (1) anterior commissure to inferior border of thyroid ala distance; (2) anterior commissure to superior border of cricoid cartilage distance; and (3) anterior commissure to inferior border of cricoid cartilage distance Results: The mean anterior commissure to inferior border of thyroid ala distance was 8.3 mm (range, 6 to 10 mm) in females and 11.8 mm (range, 10 to 13 mm) in males. The mean anterior commissure to superior border of cricoid cartilage distance was 17.5 mm (range, 15 to 21 mm) in females and 21.4 mm (range, 18 to 25 mm) in males. The mean anterior commissure to inferior border of cricoid cartilage distance was 23.7 mm (range, 20 to 27 mm) in females and 30 mm (range 26 to 35 mm) in males Conclusions: The female cadaveric larynges were, on average, smaller than those of the male counterparts studied with regard to all investigated parameters. Of specific interest was the difference in the mean anterior commissure to inferior border of thyroid ala distance between female and male specimens. Classic teaching indicates that conservation laryngeal surgery for glottic carcinoma with less than 10 mm of anterior subglottic spread is oncologically sound, because tumor would theorectically be contained within the thyroid ala. Our data suggest that use of conservation laryngeal techniques in some female patients having glottic carcinoma with less than 10 mm anterior subglottic spread may be contraindicated, because spread to the level of the cricothyroid membrane (and thus extralaryngeal access) can occur well within this distance

Time trends of lung and larynx cancers in Italy.

During the period 1970-1989, age-adjusted mortality rates for lung cancer in Italy increased by more than 50%, while rates for larynx cancer in males decreased by approximately 13%. This study aims to interpret this difference, which seems to contradict the finding that cigarette smoking is a common major risk factor for both lung and larynx cancer. To this end, we jointly analyzed the time trends of incidence, survival and mortality. We first examined survival data taken from the population-based Lombardy Cancer Registry (northern Italy). Based on data referring to 880 incident cases of larynx cancer, diagnosed during the period 1976-1987, we estimated a 3% annual increase in relative survival. By contrast, no significant period effect was observed for survival rates of 2,259 incident cases of lung cancer. National incidence rates were estimated using official mortality data and the above-described survival data. Age-adjusted estimated incidence rates increased, from 1970 to 1989, for both cancer sites: +55% for male lung, +56% for female lung, and +22% for male larynx. Moreover, the patterns of birth-cohort effect, which are diverging for mortality, are nearly parallel with regard to incidence. This analysis suggests that a substantial improvement in survival of larynx cancer patients may largely explain the differences in mortality trends for cancer of lung and larynx.

Human papilloma viruses: a study of their prevalence in the normal larynx.

The association of human papilloma viruses (HPV) with laryngopharyngeal squamous cell carcinoma is under investigation. The suitability of control tissue in the reported series, invariably obtained from histologically normal tissue adjacent to a squamous cell carcinoma or from patients with benign laryngopharyngeal disease, is questionable. The present study determined the prevalence of HPV in a series of normal larynges. Twelve autopsy larynges were collected. DNA was obtained by SDS proteinase K digestion. Evidence of HPV infection was documented by the polymerase chain reaction using oligonucleotide primers complementary to sequences in the E6 region of HPV types 11, 16 and 18. Four female and eight male larynges, mean age 65 years (SD = 16 years) were collected 72 hours postmortem (median value). HPV type 11 was isolated from three specimens. A 25 per cent prevalence rate for HPV 11 was found. No other HPV types were isolated.

Development of functional sex differences in the larynx of Xenopus laevis

Three laryngeal properties associated with the production of masculine song--laryngeal muscle tension, fiber twitch type, and fiber recruitment--are markedly sexually dimorphic in adult Xenopus laevis frogs. To elucidate the pattern of sexual differentiation, tension and fiber recruitment in male and female larynges and fiber twitch type in male larynges were examined throughout postmetamorphic development. Masculinization of male laryngeal properties begins early in postmetamorphic development and continues until adulthood. In contrast, tension and fiber recruitment in females do not change after the end of metamorphosis. Laryngeal muscle tension and fiber type are gradually and progressively masculinized; the temporal pattern of masculinization is very similar for these properties. Fiber recruitment, on the other hand, appears to masculinize in a stepwise manner. Masculinization of all three properties is highly correlated with larynx weight in males. We have used this relation to divide postmetamorphic development into seven stages associated with key events in sexual differentiation. This staging scheme provides an important experimental tool for studying the hormonal regulation of sexual differentiation, the subject of the accompanying paper.

The risk of cancer at all sites following gastric operation for benign disease. A cohort study of 4,224 patients

This report represents the results of a historical cohort analysis of 3,360 males and 864 females who had a gastric resection or gastroenterostomy for benign disease between 1990 and 1969. Within the period 1970 to 1988 the cohort was cross-checked with the data files at the Cancer Registry of Norway to identify the patients in whom cancer had been diagnosed. When analyzed according to cancer sites, increased risk was recorded for the oropharynx, stomach, colon, pancreas, liver, biliary tract, larynx, lungs, urinary bladder and non--melanomatous cancers of the skin in males. In females, increased risk was only observed for the oropharynx, but was close to a statistically significant level also for cancer of the stomach. A lower number of tumors of the central nervous system than expected was observed in both males and females. The increased risk of cancer of the lungs, larynx and urinary bladder in males can be regarded as evidence of the high prevalence of smokers in the cohort. We suggest that the increased risk of cancer of digestive organs is mainly related to life-style factors, particularly tobacco-specific nitrosamines whose effect is enhanced by surgical sequelae.

Cancers of the upper alimentary and respiratory tracts in Bombay, India: a study of incidence over two decades.

Cancers of tongue, oropharynx and larynx in males have registered a decline in incidence over the last two decades in Bombay. This decline has been shown to be a cohort effect. A synoptic measure of risk in each birth cohort, obtained by estimating site-specific cumulative incidence rate over an appropriate age range, was found useful in assessing the risk differential in successive birth cohorts. The changing pattern in incidence of cancers at several sites viz., tongue, oropharynx, and larynx, where bidi smoking is the predominant risk factor, were in conformity with the pattern expected on the basis of changing tobacco habits in the birth cohorts. However, for other sites, viz., hypopharynx, oesophagus and lung, more detailed information on relevant tobacco habits in the birth cohorts is necessary for interpreting the absence of a consistent trend in successive birth cohorts. The recent trends in per capita consumption by type of tobacco (viz., chewing/bidi/cigarette) suggest an emerging cancer pattern in the country at variance with the pattern expected from the current cancer trends in Bombay. Consequently, it is desirable to direct primary cancer prevention programmes especially to cigarette smokers in urban centres and to both bidi and cigarette smokers in the rest of the country.