Dorsal Bulge Research Articles

MORTON’S NEUROMA

Introduction: In 1876 American surgeon Thomas George Morton first detailed compressive neuropathy of the interdigital nerve of the forefoot. Mortons neuropathy occurs mostly. The condition is generated secondary to repeated pressure or irritation that leads to thickening of the nerve, located in the second or third intermetatarsal space. It is suggested that the use of pointed heel shoes could be a triggering factor for the development of this pathology due to the increased pressure on the forefoot. Objective: to describe the current information related to Mortons neuroma etiology, epidemiology, presentation, diagnosis, management and treatment. Methodology: a total of 39 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 29 bibliographies were used because the other articles were not relevant to this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: Morton, neuroma, neuritis, neuralgia, interdigital. Results: it is more frequently present in the female sex, presenting a female:male ratio of 4:1 in some bibliographies and 5:1 in others. The average age at the time of surgery is 50 years old. In 21% of the cases the neuroma is bilateral, in 66% of the cases it is related to the third space, 2% to the fourth and 32% to the second. A study showed that the average diameter of Mortons neuroma was 4.1 mm in the asymptomatic staff versus 5.3 mm in the symptomatic group. Conclusions: This condition is certainly not a neuroma as it is a degenerative rather than neoplastic condition due to fibrosis of the digital nerve. The diagnosis is primarily clinical, where there may be altered sensation and a dorsal bulge. Examinations, investigations and non-surgical treatment are the same as those used in a primary neuroma. The use of orthoses and footwear modifications is indicated for conservative treatment. For surgical treatment, dorsal and plantar approaches are used, each with their advantages and disadvantages. The dorsal incision should be extended proximally to observe the residual limb, however sometimes exposure becomes difficult. The plantar approach provides better exposure for the nerve to be easily identified and resected, however the presence of painful scarring is notable. Other complications that may occur are atrophy, recurrence and chronic pain. KEY WORDS: Morton, neuroma, neuritis, neuritis, neuralgia, interdigital.

The pharyngeal and genitalia-associated muscles of Rhabditolaimus ulmi (Nematoda: Chromodorea: Rhabditida: Diplogastridae)

Summary The copulatory organs and pharynx are important for nematode classification. This research aimed to study the musculature of the wood-inhabiting nematode, Rhabditolaimus ulmi, using confocal microscopy. The lip region is hexagonal with enlarged lateral lips; the pharynx is diplogastrid type with two bulbs. The corpus comprises the fused stegostoma, procorpus and metacorpus, with six glands opening in the stegostoma and the corpus limen. The stegostoma has a large dorsal bulge and the posterior bulb is devoid of valve, with two circles of dilators and a basal sphincter. The female genital muscles have a four-radial symmetry around the vaginal opening to the uterus. Two vaginal constrictors and four pairs of dilators of two types are connected to the vagina-uterus opening; four dilators run perpendicular to the uterus axis and are connected to the uterine muscular corset. The sphincter between the intestine and cloaca consists of the middle ring with two pairs of processes connected ventrally with intestinal fasciculi and dorsally with the body wall. The ring contains the inner biconical X-structure. In the male, the gubernaculum has the dorsal erector and a pair of transverse muscles. The wide gubernacular spicule protractor envelops spicules anteriorly. The ventral tail muscle is wide, unpaired, and nine pairs of serial diagonal muscles are located beneath the body wall muscles, followed by three pairs of postcloacal oblique muscles of the tail. Anal depressors comprise a pair of transverse muscles with expanded middle globular parts. The copulatory muscles are of the Rhabditidae and Cephalobidae type modified because of spicules elongation. The muscle characters code of the previously published tabular key for 15 muscle characters is 73422-22144-42223; it can be used for phylogenetic reconstructions.

Effect of expiratory phase for radiographic detection of left heart enlargement in dogs with mitral regurgitation.

Radiography is a standard diagnostic test for characterizing left heart enlargement in dogs however limited information is available on the effects of respiratory phases. This prospective and retrospective method comparison study investigated the respiratory effect on the size and shape of the left heart in dogs to determine the usefulness of expiratory radiographs to detect enlargements in the left atrium (LA) and left ventricle (LV). Thoracic radiographs taken at full inspiration and expiration were evaluated in 20 normal beagles and 100 dogs diagnosed with mitral regurgitation (MR). Vertebral heart score (VHS), vertebral left atrial size, elevation of the carina, and dorsal bulging of LA on lateral view and lateral bulging of the left auricular appendage and LV on ventrodorsal view were assessed. In normal dogs, there were no significant differences in the evaluative factors between inspiration and expiration. In dogs with MR, VHS did not change according to respiration. However, bulging of the LA, left auricular appendage, and LV had sharp margin during expiration compared with inspiration. The expiratory radiographic finding of LA bulging had a higher correlation with the LA to aorta ratio compared with LA bulging in the inspiratory radiography. Using a LA to aorta echocardiographic ratio greater than 1.5 as the gold standard, the radiographic sensitivity for LA enlargement was higher during expiration than inspiration. These findings of our study indicated that expiratory radiography can be helpful to support the detection of left heart enlargement, although it can overestimate LA enlargement in dogs with MR.

Imaging of the Tibionavicular Ligament, and Its Potential Role in Adult Acquired Flatfoot Deformity.

The spring ligament is an important medial arch stabilizer. However, when disrupted, it does not cause planovalgus deformity until the foot is cyclically loaded. We propose that the tibionavicular (TN) ligament plays an important role. However, this ligament is not imaged in routine magnetic resonance imaging (MRI) sequences. A prospective case-control study using a novel MRI sequence to image the TN ligament in 20 normal feet creating a baseline appearance of the ligament. We then scanned 20 patients with adult acquired flatfoot deformity (AAFD). All patients had weightbearing anteroposterior and lateral radiographs. We followed up patients, the end point being surgery or 18 months' follow-up. The normal ligament was reliably identified on the novel sequences. It had a reproducible appearance in 2 views, and consistent length and width. Two groups of patients were identified in the AAFD cohort: Normal TN (11/20) (The mean Meary angle was 6.8 degrees) and Abnormal TN (9/20). The ligament was thickened proximally, with distal attenuation and intrasubstance edema. On sagittal sequence, it had dorsal bulging and high signal. The mean Meary angle was 13.2 degrees ( P = .013). All patients had posterior tibial tendon dysfunction and 8 had spring ligament complex attenuation. Five patients have undergone corrective surgery compared to none in the other group. This study adds to the evidence that AAFD is multifactorial. With this imaging technique, we were able to reliably image the TN ligament. We hope that including this sequence into routine scanning will help us understand its role in flatfoot deformity. This poses the question of whether this structure will play a role in reconstructive surgery in future. Level II, prospective comparative study.

The Deltoid Ligament

Category: Basic Sciences/Biologics, Hindfoot, Midfoot/Forefoot Introduction/Purpose: The medial ligaments are integral in stabalising the medial column. Failure of these structures causes adult acquired flatfoot deformity (AAFD). The superomedial-cancaneonavicular component of the spring ligament(SLC) includes the medial capsule of the talonavicular joint and merges with the anterior superficial component of the deltoid complex, stabilising the talonavicular joint. However, when disrupted, it does not cause planovalgus deformity until the foot is cyclically loaded. We hypothesise that the next structure in the sequential failure cascade is the tibionavicular component of the Deltoid complex(TN) . With the failure of the SLC and the secondary effect of the posterior tibial tendon this ligament is the gatekeeper to stability of the midfoot, preventing plantar subluxation of the talus, and maintaining the radiographic lateral talo-first metatarsal angle. Methods: A prospective case control study using a novel MRI technique to image the TN. We scanned 20 consecutive normal feet and 20 with clinical and radiological AFFD. The AFFD group was subdivided into normal or abnormal TN. We assessed for pathology in the SLC, deltoid ligament (with conventional sequences) and posterior tibial tendon (PT). Imaging of the TN was performed using a novel sequence, which was an oblique view in both T1 and T2 sequence in the plane of the TN ligament to identify the normal ligament in the control group, and compare it to the patients with clinical AAFD. All patients had weight bearing AP and lateral radiographs in order to measure the calcaneal pitch, lateral talo-first metatarsal angle, and talo-calcaneal angle. We followed up patients, the end point being surgery or definitive conservative management and discharge. Results: 2 distinct groups of patients were identified. Normal TN(11/20) A mixture of medial ligament pathology was associated with this. All were managed conservatively and discharged from follow-up. The mean Meary’s angle was 6.8°. Abnormal TN(9/20) The ligament was thickened proximally, with distal attenuation and intrasubstance oedema. On sagittal sequence it had the appearance of an omega(O), with dorsal bulging and high signal on T2. The mean Meary’s angle was 13.2°(p 0.013). All patients had PT dysfunction and 8 had SLC attenuation. 5 of these patients have undergone corrective surgery. None had been discharged. The prevalence of the omega in AFFD was 30%. We confirm that the prevalence of deltoid involvement in AFFD is high, particularly in patients with more severe disease. Conclusion: Imaging of the TN is valuable in AFFD, and adds no cost or risk. There is no doubt that sequential failure of the medial ligaments occurs in AFFD. We have shown that the deltoid is involved more often than previously reported. In those with normal TN, our preliminary findings suggest that management can focus on protecting the medial structures. When the TN is attenuated(‘O’ on MRI), this represents a foot transitioning to a more severe deformity, both clinically and structurally. From our experience, these patients are more likely to have a progressive, less flexible planovalgus deformity, often requiring corrective surgery.

Two early eudicot fossil flowers from the Kamikitaba assemblage (Coniacian, Late Cretaceous) in northeastern Japan.

Two new fossil taxa referable to the basal eudicot grade are described from the Kamikitaba locality (ca. 89 MYBP, early Coniacian: Late Cretaceous) of the Futaba Group in Japan. These charcoalified mesofossils exhibit well-preserved three-dimensional structure and were analyzed using synchrotron-radiation X-ray microtomography to document their composition and internal structure. Cathiaria japonica sp. nov. is represented by infructescence segments that consist of an axis bearing three to four fruits. The capsular fruits are sessile and dehiscent and consist of a gynoecium subtended by a bract. No perianth parts are present. The gynoecium is monocarpellate containing two pendulous seeds. The carpel is ascidiate in the lower half and conduplicate in the upper part, and the style is deflected abaxially with a large, obliquely decurrent stigma. Pollen grains are tricolpate with a reticulate exine. The morphological features of Cathiaria are consistent with an assignment to the Buxaceae s. l. (including Didymelaceae). Archaestella verticillatus gen. et sp. nov. is represented by flowers that are small, actinomorphic, pedicellate, bisexual, semi-inferior, and multicarpellate. The floral receptacle is cup shaped with a perigynous perianth consisting of several tepals inserted around the rim. The gynoecium consists of a whorl of ten conduplicate, laterally connate but distally distinct carpels with a conspicuous dorsal bulge, including a central cavity. The styles are short, becoming recurved with a ventrally decurrent stigma. Seeds are ca. 10 per carpel, marginal, pendulous from the broad, oblique summit of the locule. Pollen grains are tricolpate with a reticulate exine pattern, suggesting a relationship to eudicots. The morphological features of Archaestella indicate a possible relationship to Trochodendraceae in the basal grade of eudicots. The fossil currently provides the earliest record of the family and documents the presence of Trochodendraceae in eastern Eurasia during the middle part of the Late Cretaceous.

Morphological–behavioral adaptations of two benthic invertebrate species to face strong bed hydrodynamic forces in a large South-American river

This scientific communication describes and discusses morphological–behavioral adaptations to flow of two benthic invertebrate species to survive in highly turbulent habitats of the large Paraguay River (Argentina – Paraguay). It is based on field and laboratory observations under microscope made during the performance of usual researches. In this sense, we found that Djalmabatista sp. 1 (Chironomidae, Tanypodinae) ballasts its body by ingestion of fine sediment grains which storage into a dorsal bulge, herein called “dorsal bag”. This specie would have the ability to take or release these grains according to the surrounding hydrodynamic conditions. Otherwise, the juvenile stage of Limnoperna fortunei (Bivalvia, Mytilidae) also ballasts its body but attaching sand grains through the byssal threads.

Unexpected intraoperative desaturation and lobar atelectasis due to left bronchial occlusion by concealed ascending aortic aneurysm

An 81-year-old male scheduled for debridement of a perianal abscess sustained acute upper airway obstruction with atelectasis of the left lower lobe during induction of anesthesia. Results of a fiberoptic bronchoscopy revealed dorsal bulging and obstruction of the left bronchus. Under the context of tortuous aorta and calcified left border of the heart silhouette, aortic aneurysm was suspected; the diagnosis was confirmed by a computed tomography scan. Aortic aneurysm without specific symptoms cannot be screened by a single preoperative chest X-ray. The anesthesiologist should promptly request further radiographic studies to rule out potential aortic pathology if in doubt.

Minimally Invasive Thoracic Microendoscopic Diskectomy: A Tool for All Surgeons?

One of the most common pathologic conditions encountered by spine surgeons is a herniated nucleus pulposus. The incidence of symptomatic thoracic disk herniations is <1%. The relative mobility and range of motion about the ventrally located instantaneous axis of rotation partially accounts for the frequency of herniations in the lumbar and cervical spine. The thoracic spine is comparatively immobile with the sternum and rib cage providing substantial structural support, with a commensurate restriction of motion. Paraspinal muscles also contribute to diminished mobility, whereas the natural kyphosis of the thoracic spine limits the incidence of dorsal disk and annulus bulging. The structures that provide such immobilization making herniated nucleus pulposus less common in the thoracic region also serve as a barrier, of sorts, to the surgeon for surgical intervention. The transthoracic, transthoracic extrapleural, costotransversectomy, and dorsal approaches all are associated with significant drawbacks from an exposure and technical perspective. None of these approaches can be universally employed, and each is associated with approach-specific obstacles. The location, laterality, and characteristics of a disk herniation play a key role in the surgical decision-making process. A central calcified disk is better addressed through a ventral or far lateral approach, whereas a soft lateral disk herniation may be better managed via a dorsolateral approach. Patient presentation may vary, depending on the location and magnitude of the herniation. For far lateral disk herniations, radicular pain may be the presenting complaint. An acute central disk herniation may cause rapid onset of myelopathy. Upper thoracic to midthoracic disk herniations may cause a deep chest pain that can be mistaken for cardiac pain. Midthoracic to lower thoracic disk herniations may masquerade as renal colic or gastrointestinal pain. The ultimate key to the decision-making process is careful physical examination in conjunction with obtaining appropriate imaging studies.

A new fossil rorqual (Mammalia, Cetacea, Balaenopteridae) from the Early Pliocene of the North Sea, with a review of the rorqual species described by Owen and Van Beneden

ABSTRACT A fossil rorqual — Diunatans luctoretemergo n. gen., n. sp. — is described based on two specimens from the early Pliocene of The Netherlands and is compared to all previously described rorquals. The morphology of the new species, especially that of the elements of the petrotympanic complex, is described in detail. Main discriminating characters are: very short nasal; mediolaterally wide pterygoid fossa; large, robust and prominent occipital condyle; mediolaterally wide squamosal body lateral to the supraoccipital; dorsal bulge on squamosal; tympanic bulla very large compared to zygomatic width; wide tympanic bulla (L/W ratio: 1.24) with the sigmoid process perpendicular to the long axis of the bulla; rounded and bulbous pars cochlearis (L/W ratio: 1.23–1.26); long, slender and curved stapes; massive and square basioccipital process; wide basioccipital. A phylogenetic analysis has been undertaken based on a recently published matrix. In the consensus tree the new taxon has a basal position with re...

Traumatic intracorporal septal avulsion resulting in cavernous veno-occlusive dysfunction

A 44-y-old man was evaluated for ED 4 months after an untreated penile fracture. During the initial incident, the patient felt a ‘snap’ during intromission, followed by pain, detumescence, bruising of the penile shaft, and blood at his urethral meatus. He reported penile rigidity as 5/10, with a ‘bulge’ on the dorsum of the shaft during maximal rigidity. His ED did not improve with sildenafil citrate. He denied penile curvature or pain. Physical examination revealed dorsal mid-shaft thickening of the corporal bodies without a discrete plaque of the tunica albuginea. Urinalysis and retrograde urethrogram were normal. During penile duplex doppler ultrasound with intracavernosal injection of PGE-1, he obtained 50% rigidity after self-stimulation and we made the following measurements on the right and left sides, respectively: peak systolic velocity 32.4 and 53.5 cm/s; end diastolic velocity 8.0 and 11.4 cm/s; resistive index 0.68 and 0.71. With erection, a 3 cm ballotable area on the dorsal shaft appeared. Ultrasound of this region demonstrated absence of the septal insertion into the dorsal tunica albuginea (Figure 1). Figure 1a demonstrates the normal appearance of the intracorporal septum as it inserts into the dorsal tunica in the proximal penile shaft. Dynamic infusion cavernosometry and cavernosography with injection of papaverine demonstrated a flow-to-maintain rate greater than 140 ml/min with outflow of contrast to the deep dorsal vein. We began penile reconstruction by degloving the penis, elevating the dorsal vein, and ligating it at the proximal shaft. Artificial erection demonstrated a dorsal bulge of the tunica albuginea (Figure 2a) that was incised longitudinally, confirming a 3.5 cm avulsion of septum from the dorsal tunica. We used 4.0 Maxon sutures to imbricate the dorsal tunica albuginea with reattachment to the septum. Artificial erection verified absence of the dorsal bulge and straightness of the penis without narrowing (Figure 2b). After 1 month, the patient resumed intercourse. After 1 y, he continues to have rigid erections, sufficient for intercourse, and equivalent to his baseline.

APPLICATION OF PERICARDIAL GRAFT IN THE SURGICAL MANAGEMENT OF PEYRONIE’S DISEASE

We investigated the use of Tutoplast cadaveric pericardium as an alternative material for grafting the tunica albuginea defect after Peyronie's plaque excision. A total of 11 patients with significant penile curvature interfering with sexual intercourse were evaluated after at least 12 months of conservative therapy. Preoperative evaluation in all cases included penile duplex Doppler ultrasound studies. Chemically processed and gamma irradiated pericardium was used to graft the cavernosal defect after surgical excision of the penile plaque. In 3 patients a penile prosthesis was simultaneously placed secondary to documented erectile dysfunction at duplex Doppler ultrasound evaluation. Penile curvature resolved in all patients, allowing for normal sexual function after a mean followup of 14 months (range 9 to 19). No postoperative evidence of tissue rejection or infection was noted. In 1 patient urethro-corporal communication developed and a single penile cylinder was explanted. Another patient had a mild dorsal bulge at the site of graft placement when the prosthesis was fully inflated. Polymeric silicone material used to provide satisfactory results in the surgical treatment of Peyronie's disease but it is no longer available for biomedical use. We demonstrate the effective use of cadaveric pericardium as a graft material for cavernosal defects after Peyronie's plaque excision. Overall patient satisfaction, absence of a second surgical incision, relative low risk and ease of surgical placement make this material ideal for the surgical treatment of this disease process.

The Choroid Plexus in Normal Full-term Neonate: A Study of Morphological Variety on Sonography

Purpose : The purpose of this study was to evaluate the sonographic features of normal choroid plexus, thushelping avoid misinterpretations such as intraventricular hemorrhage or abnormality. Materials and Methods :Posterior coronal, parasagittal, and oblique sagittal scans of 400 choroid plexus in normal full-term neonates(100girls, 100 boys) were reviewed with special attention to coronal configuration, glomus patterns, and the shape of anterior ends. Sonographic features were classified as follows ; tubular(type 1), posterior clubbing(type 2),mid-bulging(type 3), or double choroidal pattern(type 4), as seen on posterior coronal scans; crescent(type1),superior notching(type 2), dorsal bulging(type 3), or inferior notching(type 4), as seen on parasagittal scans; and anterior tapering(type 1) and clubbing shape (type 2) on oblique parasagittal scans. Maximal diameters of the choroid plexus on posterior coronal scan and the glomus on parasagittal scan were measured. All sonographic measurements of normal choroid plexus were statistically analysed according to gender and side. Results : Four hundred normal choroid plexus were classified as 293 cases(73%) of tubular pattern(type 1), 50 cases(13%) ofposterior bulging(type 2), 44 cases (11%) of mid-bulging(type 3) and 13 cases(3%) of double choroidal pattern(type 4) as seen on posterior coronal scans ; 263 cases(66%) of crescent shape(type 1), 70 cases(17%) of superiornotching (type 2), 38 cases(9%) of dorsal bulging(type 3), and 29 cases(7%) of inferior notching(type 4), as seenon parasagittal scans; and 233 cases(58%) of anterior tapering(type 1) and 167 cases(42%) of anterior clubbing(type 2), as seen on oblique parasagittal scans. Maximal diameters of the choroid plexus on posterior coronal scanwere (95% confidence interval [CI]) on the right side and (95% CI) on the left side, and (95% CI) mm on the right and on the left side glomus on parasagittal scan. There were no significant statistical differences with regard to gender and side. Conclusion : We have observed the morphological variety of the choroid plexus in normal full-term neonates on ultrasonograms and believe that a knowledge of the various sonographic patterns involved can help differentiating normal choroid plexus from intraventricular hemorrhage or choroidal abnormality.

AM67, a Secretory Component of the Guinea Pig Sperm Acrosomal Matrix, Is Related to Mouse Sperm Protein sp56 and the Complement Component 4-binding Proteins

The guinea pig sperm acrosomal matrix is the dense core of the acrosome and is likely to be important in acrosome biogenesis and fertilization. Isolated acrosomal matrices are composed of a limited number of major bands when analyzed by SDS-polyacrylamide gel electrophoresis, among which is a Mr 67,000 protein that we have termed AM67. Indirect immunofluorescence demonstrated that AM67 is localized to the apical segment of the cauda epididymal sperm acrosome. Immunoelectron microscopy further refined the localization of AM67 to the M1 (dorsal bulge) domain within the acrosome. Using a polymerase chain reaction product based upon tryptic peptide sequences from AM67, a lambdagt11 guinea pig testis cDNA library was screened to yield two cDNA clones that encode the AM67 peptides. Northern analysis revealed that AM67 is transcribed as a 1. 9-kilobase testis-specific mRNA. The complete AM67 sequence encodes a prepropolypeptide of 533 amino acids with a calculated Mr of 59, 768. Following cleavage of a probable signal sequence, the polypeptide was predicted to have a Mr of 56,851 and seven consensus sites for asparagine-linked glycosylation. The deduced amino acid sequence of AM67 is most similar to those of the mouse sperm protein sp56 and the alpha-subunits of complement component 4-binding proteins from various mammalian species. Although mouse sp56 has been reported to be a cell-surface receptor for the murine zona pellucida glycoprotein ZP3, standard immunoelectron microscopy using the anti-sp56 monoclonal antibody 7C5 detected sp56 within the mouse sperm acrosome, but failed to detect sp56 on the surface of acrosome-intact mouse sperm. Furthermore, acrosomal labeling was detected in mouse sperm prepared for immunofluorescence using paraformaldehyde fixation, but was not observed with live unfixed sperm. Thus, the finding that sp56 is present within the acrosome provides further support that sp56 and AM67 are orthologues and suggests that sp56 may function in acrosomal matrix-zona pellucida interactions during and immediately following the acrosome reaction in the mouse.

Teratogene und metamorphosehemmende Wirkung von Retinsäure in Ciona intestinalis / Teratogenic and Metamorphosis-Inhibiting Activity of Retinoic Acid in Ciona intestinalis

Exposure of embryos of the sea squirt, Ciona intestinalis, to all-trans-retinoic acid (between 10(-5) and 10(-7) M) causes specific malformations of the larvae and suppression of settlement and metamorphosis. Whether the vitamin A derivative was administered at the 2-cell stage, or at the early gastrula stage did not affect the nature of the extent of the ensuing anomalies. Malformations include a dorsal bulge of the body, an irregular disposition of ocellar pigment, and a twisted tail. Treated larvae have no statocyst pigment. There is also a reduction in size of the body, compared to control larvae. Retinoic acid retarded hatching, or even blocked it (at 10(-5) M). Obviously retinoic acid interferes with the induction of metamorphosis, possibly through neutralizing one or more factors responsible for settlement and metamorphosis. The possible role of thyroxin in these processes is being critically evaluated.

Evidence for sequential deployment of secretory enzymes during the normal acrosome reaction of guinea pig sperm in vitro.

Experiments were conducted to determine if acrosomal enzymes are released simultaneously or in sequence during the normal acrosome reaction. Epididymal guinea pig sperm were incubated in a chemically defined, calcium-containing medium which supports normal acrosome reactions within 4-5 hours at 37 degrees C. The sperm suspensions were monitored for motility, normal acrosome reactions, and false acrosome reactions during in vitro incubation. At specified time intervals, the sperm were separated from the incubation medium by centrifugation, and the distribution of dipeptidyl peptidase (DPP II) and acrosin activity was determined by biochemically assaying the hydrolysis of trialanine and N-benzoyl-L-arginine ethyl ester (BAEE), respectively. When calcium was present, there was a significant increase in DPP II activity in the supernatants by 1 hour of incubation and a slight decline at later time points. This release was not correlated with false or normal acrosome reactions (loss of the acrosomal cap) monitored by phase-contrast microscopy but probably represents a very early stage in the normal acrosome reaction. This early stage is difficult to detect at the light microscope level because sperm are still in rouleaux and because membrane fusion is not directly observable. In contrast, acrosin activity, which was assayed in the same supernatants, increased at later times when sperm were observed to have completed normal acrosome reactions. The ultrastructural distribution of DPP II was determined in sperm pellets collected during in vitro incubation by using the DPP II substrate lysyl-alanyl-4-methoxy-2-naphthyamide. In freshly isolated cauda epidiymal sperm, reaction product is confined to the light-staining area in the dorsal bulge of the acrosome. However, by 1 hour of incubation, the light-staining area of many sperm was partially or completely dispersed, while other regions of the acrosome were unchanged. Our data are consistent with the conclusions that DPP II is a highly soluble component of the guinea pig sperm acrosome and that its release occurs during the initial phase of the acrosome reaction while sperm are still in rouleaux. Structural changes in the acrosome associated with DPP II release were detectable by electron microscopy but not by light microscopy. Acrosin, which is less soluble than DPP II, is released at a later time during the acrosome reaction. Both DPP II and acrosin appear to be partially inhibited following their release from sperm. A complete understanding of the sequential release and extracellular activities of the acrosomal enzymes will be necessary to fully define their functions in fertilization.

Cytochemical localization of dipeptidyl peptidase II (DPP-II) in mature guinea pig sperm.

Guinea pig sperm contain the exopeptidase dipeptidyl peptidase II (DPP-II). Our purpose was to localize this enzyme in sperm at the ultrastructural level using lysylalanyl-4-methoxy-beta-naphthylamide which is the specific synthetic substrate for DPP-II. In substrate incubated sperm, reaction product was located within the acrosome. It was concentrated over the light staining area which forms the prominent dorsal bulge of the acrosome. Within this area there are spherical zones of moderate electron density which had little or no reaction product. Control sperm did not have reaction product. We conclude that DPP-II is restricted to a compartment within the guinea pig sperm acrosome.