Lateral Calf Research Articles

Nonsurgical treatment for radicular of pain of zygoapophyseal joint cyst origin: Therapeutic selective nerve root block

Slipman CW, Lipetz JS, Herzog RJ, Vresilovic EJ. Nonsurgical treatment for radicular pain of zygoapophyseal joint cyst origin: therapeutic selective nerve root block. Arch Phys Med Rehabil 2000;81:1119-22. We report the first case of zygoapophyseal joint cyst–induced radicular pain successfully treated with therapeutic selective nerve root block. A 56-year-old dentist presented with pain involving the lateral thigh, lateral calf, and foot dorsum that worsened with standing and walking. Magnetic resonance imaging of the lumbar spine showed a cyst emanating from the right L4-L5 zygoapophyseal joint, resulting in central canal and lateral recess stenosis. The patient was treated with two fluorscopically guided therapeutic L5 selective nerve root blocks. The patient remained pain free at 18-month follow-up. © 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Nonsurgical treatment for radicular of pain of zygoapophyseal joint cyst origin: Therapeutic selective nerve root block

Slipman CW, Lipetz JS, Herzog RJ, Vresilovic EJ. Nonsurgical treatment for radicular pain of zygoapophyseal joint cyst origin: therapeutic selective nerve root block. Arch Phys Med Rehabil 2000;81:1119-22. We report the first case of zygoapophyseal joint cyst–induced radicular pain successfully treated with therapeutic selective nerve root block. A 56-year-old dentist presented with pain involving the lateral thigh, lateral calf, and foot dorsum that worsened with standing and walking. Magnetic resonance imaging of the lumbar spine showed a cyst emanating from the right L4-L5 zygoapophyseal joint, resulting in central canal and lateral recess stenosis. The patient was treated with two fluorscopically guided therapeutic L5 selective nerve root blocks. The patient remained pain free at 18-month follow-up. © 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Diameter-reflux relationship in perforating veins of patients with varicose veins

Purpose: Treatment of chronic venous valvular insufficiency requires understanding of the hemodynamics of perforating veins. To preserve normal veins or veins that can function normally once primary sources of valvular insufficiency are removed, a better understanding of the diameter-reflux relationship is desirable. We measured reflux and diameters in 500 perforating veins of patients with varicose veins (C 2E PA SPP R). Methods: Color flow duplex ultrasonography scanning was performed with the patient standing. Perforating veins were mapped medially in the thigh and medially, laterally, and posteriorly in the calf. Reflux was defined as reverse flow that lasted longer than 0.5 seconds. Diameters were measured on B-mode transverse projections at the crossing of the fascia. Competent versus incompetent vein diameters were compared by means of Student t test, one-way analysis of variance, and Bonferroni t test. Results: Diameters of competent and incompetent perforators averaged 2.5 ± 0.9 mm (n = 17) and 4.7 ± 1.9 mm (n = 17) at the medial thigh ( P < .0002), 2.2 ± 0.8 mm (n = 179) and 3.7 ± 1.0 mm (n = 210) at the medial calf ( P < .0001), 2.2 ± 0.6 mm (n = 13) and 3.5 ± 0.8 mm (n = 37) at the posterior calf ( P < .0001), and 2.1 ± 0.8 mm (n = 9) and 3.3 ± 0.7 mm (n = 18) at the lateral calf ( P < .003), respectively. Perforating vein diameters of 3.5 mm or larger in the calf and thigh were associated with reflux in more than 90% of the cases. Conclusion: An enlargement in the diameter of the perforating veins of 1 to 1.5 mm in the calf or 2 mm in the thigh of patients with varicose veins could be the difference between normal flow and reflux. Further studies are needed to confirm if elimination of reflux in patients with primary varicosity will transform incompetent perforators to competent ones. (J Vasc Surg 1999;30:867-75.)

Increased nerve growth factor mRNA in lateral calf skin biopsies from diabetic patients.

This study set out to establish a novel procedure for the measurement of human nerve growth factor (NGF) messenger ribonucleic acid (mRNA) and to use this method to measure NGF expression in skin biopsies from control subjects and from patients with early neuropathies. NGF mRNA levels were related to functional measures of the competence of NGF-responsive nerves. mRNA levels were measured by competitive reverse transcription with polymerase chain reaction amplification (cRT-PCR). Functional correlates of this observation were assessed by indices of thermal sensitivity--mediated by C-fibres, whose phenotype is regulated by NGF. NGF mRNA was increased in skin biopsies from 19 diabetic patients (5.12+/-3.88 (SD)) compared with samples from eight controls (1.57+/-0.95; P=0.001). Diabetic patients showed significantly (P < 0.001) diminished detection of cool and warm stimuli compared to age matched control group (n=24), but there were no differences in detection of heat as pain, or correlation with NGF mRNA levels. These findings suggest abnormally increased expression of NGF in diabetic neuropathy, which may represent a compensatory mechanism for impaired phenotype in NGF-responsive neurones.

Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides in male volunteers

Study Objectives: To test the effect of stellate ganglion block on tympanic membrane temperatures. Design: Prospective, observational study. Setting: Department of Anesthesia, Yamanashi Medical University, Yamanashi, Japan. Subjects: 7 healthy male volunteers. Interventions: Stellate ganglion block, 6 ml of 1% mepivacaine hydrochloride, was administered. Measurements and Main Results: Application of temperature probes (right and left tympanic membranes, eight adhesive right skin-surface temperatures at the chest, upper arm, digital fingertip, lateral calf, thigh, and great toe) was followed by a 30-minute control period. Temperatures were recorded every 15 minutes for 30 minutes before stellate ganglion block and every 5 minutes for 40 minutes after the block. The right tympanic membrane temperature increased slightly but not significantly compared with the left tympanic membrane temperature 10 minutes after stellate ganglion block and subsequently. Right skin-surface temperature gradients at the upper limb decreased slightly but not significantly after stellate ganglion block. Similarly, right skin-surface temperature gradients at the lower limb decreased slightly but not significantly after stellate ganglion block. Conclusions: Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides.

Cutaneous hemoglobin oxygenation of different free flap donor sites.

Microsurgical skin flaps raised from various body regions show differences in vascular architecture, cutaneous capillary density, and skin perfusion. Therefore, it can be expected that oxygenation of the skin is different at the various free flap donor sites. To determine the cutaneous oxygen supply, intracapillary hemoglobin oxygenation was measured on the donor sites of the radial forearm flap, scapula, latissimus dorsi, rectus abdominis, anterolateral thigh, and osteocutaneous fibula flap on 50 healthy subjects (25 men and 25 women aged 20 to 40 years). Measurements were performed noninvasively with the Erlangen Microlightguide Spectrophotometer (EMPHO) on skin areas of 6 x 8 cm in each region under resting conditions. The hemoglobin oxygenation of the skin in all donor regions varied between a maximum of 43.94 to 58.94 percent in the scapula region and a minimum of 13.89 to 29.45 percent in the lateral calf. High oxygenation values were also found on the skin over the latissimus dorsi muscle (34.56 to 48.45 percent), followed by the distal volar forearm (29.78 to 40.30 percent), whereas paraumbilical skin and the donor sites of the lower extremities were less oxygenated. By using the Wilcoxon test, significant differences were found between all donor regions except for the anterolateral thigh and lateral calf (p = 0.05). There were no gender-specific differences. From these results, it is concluded that, on young healthy subjects, regional oxygen supply on different free flap donor sites varies significantly. This finding must be considered in the interpretation of intracutaneous or transcutaneous PO2 measurements for flap monitoring.

Measuring venous capacitance and blood flow in pregnancy.

Forearm or calf venous plethysmography has been used in pregnant women to examine the effects of pregnancy on the vascular system and more recently to measure blood flow changes in response to intra-arterial infusion of vasoactive substances. To examine the assumption that venous capacitance and blood flow measurements are the same in the forearm and calf, venous plethysmography was conducted simultaneously on the forearm and calf in normal (NP) and hypertensive pregnant women (HTP) in their third trimester and in normal nonpregnant women (N). All studies were made on the right forearm and calf with subjects in the left lateral recumbent position. There was no significant difference between venous capacitance in the forearm (median: 124 x 10(3)mL/100mL/mmHg for both NP and HTP) and leg (134 [NP] and 106 [HTP] x 10(3)mL/100mL/mmHg) for both pregnant groups but venous capacitance in the nonpregnant group was greater in the leg than arm (174 versus 112 x 10(3)mL/100mL/mmHg, p < 0.001). Blood flow was similar in the leg and forearm (median 4.9 versus 3.9mL/100mL/min respectively) in nonpregnant women. Forearm blood flow was also similar to calf flow in NP women (6.2 versus 4.3mL/100mL/min respectively) but greater than calf blood flow in HTP (9.7 versus 5.3mL/100mL/min, p < 0.01). Using left lateral recumbency, forearm and calf vein capacitances are similar in pregnant women, in contrast to nonpregnant women. Blood flow is higher in the forearm than the calf only in hypertensive pregnant women. These observations should be borne in mind when interpreting studies of regional blood flow in pregnancy.

Optimal methods for autogenous bypass to the anterior tibial artery

Autogenous bypass to the anterior tibial artery (AT) has been increasingly used for infrageniculate revascularization. The conduit may be routed through the interosseous membrane, a pretibial tunnel, or through a lateral thigh and calf tunnel. This study reviewed results of AT bypass to determine the optimal routing method. One hundred thirty consecutive vein grafts to the AT were analyzed retrospectively to compare the experience with the interosseous (group I; n = 50), pretibial (group II; n = 51), and lateral (group III; n = 29) routing alternatives. Indications were claudication in 16 (12.3%) and critical ischemia in 114 (87.8%) procedures with no differences among routing subgroups. Ectopic nonreversed and composite conduits were more common in group III. Major operative morbidity occurred after 7 procedures (5.4%) with no differences in early graft failure (7.7% overall) among the three routing subgroups. Wound infections were more common among group I patients, but without predilection to the interosseous tunnel. During a mean follow-up of 24.9 months (0 to 111.2) overall 5-year secondary patency was 70% with no difference among routing technique. Optimal routing choice depends on the location of suitable AT, the length of adequate vein conduit, and the surgeon's preference rather than on factors inherent to the method used.

I.m. midazolam as premedication produces a concentration-dependent decrease in core temperature in male volunteers

We tested the hypothesis that premedication with i.m. midazolam decreases core temperature dose-dependently. We studied six male volunteers, in random order, on 3 days: (1) no midazolam administration (control day), (2) midazolam 0.025 mg kg-1 i.m., (3) midazolam 0.075 mg kg-1 i.m. On the first day, subjects were maintained alert during a 30-min control period. On the second and third days, midazolam 0.025 or 0.075 mg kg-1 was administered i.m. Core temperatures were measured at the right tympanic membrane. Four adhesive skin surface probes were fixed on the chest, upper right arm, lateral calf and thigh. Finger tip perfusion was evaluated using forearm minus fingertip and calf minus toe, skin surface temperature gradients. Thirty minutes after midazolam i.m., the level of sedation in the volunteers was assessed. Peripheral venous blood was obtained immediately after the assessment of the level of sedation. Tympanic membrane temperatures after administration of midazolam 0.075 mg kg-1 i.m. were significantly lower than those on the control and midazolam 0.025 mg kg-1 i.m. days at 20 and 30 min. The decreases in tympanic membrane temperatures at 30 min after midazolam i.m. became larger as the volunteers were more deeply sedated. i.m. midazolam produced a concentration-dependent decrease in tympanic membrane temperature at 30 min after midazolam 0.025 and 0.075 mg kg-1 i.m. We conclude that midazolam impaired tonic thermoregulatory vasoconstriction, allowing core-to-peripheral heat redistribution in a dose-dependent manner after i.m. administration.

Muscle afferents innervating skin form somatotopically appropriate connections in the adult rat dorsal horn.

We have studied the somatotopic reorganization in dorsal horn neurons after a disruption in the normal spatial arrangement of primary sensory axons in adult rats. Muscle afferents were redirected to skin by cutting and cross-anastomosing the hindlimb gastrocnemius nerve (GN) and sural nerve (SN). It has previously been shown that after 10-12 weeks GN afferents innervate the hairy skin of the lateral ankle and calf (previously innervated by SN afferents) and become potentially capable of relaying information on the location and intensity of stimuli applied to the skin. We determined the receptive field and response properties of dorsal horn neurons in the lumbar spinal cord, in regions where the lower hindlimb is normally represented. In control animals (with intact or self-anastomosed sural nerves) very few neurons (< 8%) received any synaptic input from the GN as assessed by electrical stimulation of the nerve. In contrast, when this nerve innervated skin, many cells responded to GN stimulation, and these nearly all had receptive field components in the former SN territory. Moreover, in animals with cross-anastomosed nerves, cells without GN inputs all had receptive fields outside the former SN skin territory. We have shown that in all likelihood GN afferents substituted for SN afferents in subserving the low and high threshold receptive fields of dorsal horn neurons. Furthermore, for many neurons, receptive fields were formed from inappropriately regrown GN afferents and adjacent intact cutaneous afferents (in the tibial or common peroneal nerves). Therefore, when GN afferents innervate skin in adult animals, they alter their central connectivity in an appropriate manner for their new peripheral terminations, so that an orderly somatotopic representation of the hind limb skin is maintained. We suggest that this plasticity of dorsal horn somatotopy is driven in part by activity-dependent mechanisms.

Body site variation of cool perception thresholds, with observations on paradoxical heat.

Thresholds for the perception of coolness and heat pain were determined in sessions that randomly intermixed temperature increases and decreases. Four body sites were tested bilaterally: thenar eminence of the hand, plantar surface of the foot, dorsolateral forearm, and lateral calf. Coolness thresholds were lowest for the hand, intermediate for the forearm, and highest for the leg and foot. Laterality differences were not statistically significant. In 34% of the sessions, subjects did not consistently report cool or cold sensations with detectable temperature decreases. When they did not report cool or cold, they most often reported heat or pain, thus exhibiting the phenomenon of "paradoxical heat." There were significantly more paradoxical heat responses when cooling stimuli were intermixed with painfully hot stimuli than when they were intermixed with only warm stimuli. There was no significant correlation observed between thresholds for coolness and heat pain, either across body sites or across subjects at any single body site. This result implies that the various factors relevant to thermal sensitivity (i.e., thermal properties of the epidermis, innervation density) are differentially important for cool versus heat pain perception.

Body site variation of heat pain sensitivity.

Thirty-two healthy human subjects provided thresholds for the perception of slight and moderate heat pain. Four body sites were tested bilaterally: thenar eminence of the hand, plantar surface of the foot, dorsolateral forearm, and lateral calf. Thresholds for the glabrous skin of the hand and foot were significantly greater than thresholds for the hairy skin of the arm and leg, the average difference being 1.3 degree C. Laterality was not a statistically significant factor. Thresholds increased progressively over 2-4 weeks of repeated testing, resulting in values averaging 0.6 degree C higher in the later sessions. The difference between moderate and slight pain thresholds averaged 1.1 degree C, and was consistent across body sites and with repeated testing. The threshold values were normally distributed across subjects. Considerable intersubject variability was observed for both slight and moderate pain thresholds, more so on glabrous than on hairy skin sites. In comparison, the distribution of right-left difference values was narrower, demonstrating less intrasubject versus intersubject variability. The highly significant difference in thresholds between glabrous and hairy skin sites demonstrates the importance of skin type for heat pain sensitivity. In contrast, there was no significant difference in heat pain sensitivity between comparable sites on the upper versus lower extremities, or between left and right sides.

Subcutaneous or intramuscular insulin injections.

To find out whether diabetic children may inject their insulin intramuscularly rather than subcutaneously, a random sample of 32 patients aged 4.3-17.9 (median 11.3) years was studied. Distance from skin to muscle fascia was measured by ultrasonography at standard injection sites on the outer arm, anterior and lateral thigh, abdomen, buttock, and calf. Distances were greater in girls (n = 15) than in boys (n = 17). Whereas in most boys the distances were less than the length of the needle (12.5 mm) at all sites except the buttock, in most girls, the distances were greater than 12.5 mm except over the calf. Over the fascial plane just lateral to the rectus muscle the distance from skin to peritoneum was less than 12.5 mm in 14 of the 17 boys and one of the 15 girls. Twenty five of the 32 children injected at an angle of 90 degrees, and 24 children raised a skinfold before injecting. By raising a skinfold over the anterior thigh, the distance from skin to muscle fascia was increased by 19% (range 0-38%). We conclude that most boys and some girls who use the perpendicular injection technique may often inject insulin into muscle, and perhaps on occasions into the peritoneal cavity.

Long-term changes in purposive and reflexive responses to nociceptive stimulation following anterolateral chordotomy

Macaca nemestrina monkeys received unilateral interruption of the spinothalamic tract, producing contralateral hypalgesia and a bilateral decrease in amplitude of the flexion reflex. These effects on operant escape and reflex responses to electrocutaneous stimulation (ES) were monitored for months to evaluate relationships between the extent of each lesion and the presence or absence of recovery from the early postoperative deficits. Before surgery, the animals were trained to perform an operant response that terminated ES to the lateral calf of either leg. The durations of ES tolerated by each monkey were inversely related to stimulus intensities within the pain sensitivity range of human subjects. The vigor of operant escape responses and the frequency of intertrial pulls of the manipulandum were directly related to stimulus intensity. Following anterolateral chordotomy at an upper thoracic level, these measures revealed a contralateral hypalgesia for each animal. Operant responsivity to stimulation contralateral to the lesion recovered to control levels for 7 animals (group R). Sustained contralateral recovery of operant reactivity was not observed for 8 monkeys (group U). Most of the lesions in groups R and U were similar in extent and location, involving the classical distribution of the spinothalamic tract (in the anterolateral and ventral columns). Thus, recovery was not determined solely by lesion configuration. However, when recovery did occur, it was associated with medially extensive lesions. A subgroup of 3 unrecovered animals received superficial lesions that did not substantially involve the gray matter or the ventral columns. For all animals, reflex magnitudes were initially diminished bilaterally and then increased over months of testing. Reflex recovery was greater for the animals that demonstrated recovery of intentional reactions to nociception (group R). An ipsilateral hyperreflexia became apparent for group R. Contralateral recovery to normal levels was observed for group R but not for group U. The time course of recovery for operant and reflex responses clearly differed, indicating that different processes determined changes in these spinal and supraspinal reactions to nociceptive stimulation.

Functional and morphological changes in the eccrine sweat gland with heat acclimation

Three adult male patas monkeys (11-15 kg) were heat acclimated by continuous exposure to an ambient temperature of 33 +/- 1 degree C at 13% relative humidity for 9 mo. During the last month, they were also exposed to 45 degrees C at 10% relative humidity for 4 h/day and 5 days/wk. Before and after 3 wk of acclimation, the animals were given a heat-tolerance test in which rectal (Tre) and mean skin (Tsk) temperatures, heart rate, and sweat rate (msw) were monitored during a 90-min exposure to 45 degrees C heat with 24% relative humidity under lenperone (1.0-1.4 mg/kg im) tranquilization. Maximal in vivo msw was also determined in response to subcutaneous injections (1 and 10% solutions) of methacholine (MCh). Before and after 9 wk and 9 mo of acclimation, sweat glands were dissected from biopsy specimens of the lateral calf, cannulated, and stimulated in vitro with MCh. Morphological measurements of isolated tubules were compared with maximal secretory rates produced by MCh stimulation. Three weeks of acclimation 1) reduced Tre and Tsk and increased msw during the heat tolerance test and 2) significantly increased maximal msw in response to MCh stimulation. Acclimation also increased (P less than 0.05) sweat gland size, as measured by tubular length and tubular volume. Maximal in vitro msw produced by MCh stimulation and msw per unit length of secretory coil also increased significantly. We conclude that heat acclimation increases the size of eccrine sweat glands and that these larger glands produce more sweat. They are also more efficient because they produce more sweat per unit length of secretory coil.

Changes of the spinal evoked potential induced by lateral compression of the spinal cord in dogs

To investigate the influence of chronic nociceptive pain on endogenous pain modulation, the effect of heterotopic noxious conditioning stimulation (HNCS) on perception of various somatosensory modalities was assessed in 15 patients with painful osteoarthritis of the hip. Thirteen patients were re-assessed when pain-free 6–14 months following surgery. Sex- and age matched healthy subjects assessed at similar time intervals served as controls. The effects of HNCS were tested using the upper extremity submaximal effort tourniquet test. Subjects rated tourniquet-induced pain intensity on a visual analogue scale (VAS). Quantitative sensory testing (QST) was performed contralaterally to the maximally painful area in 13 patients and contralaterally to the second most painful area in two patients (i.e. lateral thigh n=12, frontal thigh n=1, lateral calf n=2). Sensibility was assessed before, during and 45 min following the tourniquet test. Perception thresholds to light touch were assessed using von Frey filaments and pressure pain thresholds by pressure algometry. Perception thresholds to non-painful and painful warmth and cold were determined using a Thermotest. In both sessions, patients rated the tourniquet-induced pain higher than controls at the start (P<0.003 and P<0.006, respectively), but not at the end of the tourniquet test. Decreased sensitivity to light touch (P<0.001) and innocuous cold (P<0.002) was seen during the tourniquet in patients and controls alike, on both occasions, while perception thresholds to innocuous warmth and heat pain remained unaffected. In the first session, pressure pain thresholds increased during the tourniquet test in controls (P<0.002), but not in patients. In the second session, pressure pain thresholds increased during the tourniquet test in controls (P<0.001) and in patients (P<0.02). In conclusion, no pressure pain modulation was induced by HNCS in patients before surgery, as opposed to controls, suggesting a dysfunction in systems subserving ‘diffuse noxious inhibitory controls’ (DNIC). Normal pressure pain modulation induced by HNCS was seen when patients were re-assessed in a pain-free state following surgery, indicating that the dysfunction of DNIC had been maintained by chronic nociceptive pain.

Fatness and fat patterns: associations with plasma lipids and blood pressures in adults, 18 to 57 years of age.

As a part of the Fels Body Composition Study (an extension of the Fels Longitudinal Study in Yellow Springs, Ohio), the hypothesis was examined that a centripetal fat pattern, characterized by a greater proportion of trunkal than extremity adiposity, was associated independent of age and per cent body fat with levels of plasma lipids and lipoprotein cholesterols and blood pressures. A cross-sectional sample of 303 white men and women, 18 to 57 years of age, measured between September 1976 and August 1979, was selected without regard to diagnosis of hypertension, hyperlipidemia, or obesity. The degree of centripetal adipose tissue distribution was indexed by the logarithm of the ratio of the subscapular to lateral calf skinfold thicknesses. Per cent body fat was estimated by densitometry. In multiple regression equations controlling for age, age2, and per cent body fat, centripetal fat pattern had a small but significant positive association with systolic blood pressure in men (R2 = 0.02, p less than 0.05). In women, centripetal fat pattern had small but significant positive associations with plasma triglycerides (R2 = 0.05, p less than 0.005), and a significant negative association with plasma high density lipoprotein cholesterol (R2 = 0.08, p less than 0.0005) after effects due to age, age2, and per cent body fat had been removed. Centripetal fat patterns appear to be associated with an "atherogenic" lipid profile in women, but the association in men is confounded with effects due to age and total body adiposity.

The Diabetes Alert study: growth, fatness, and fat patterning, adolescence through adulthood in Mexican Americans.

Diabetes Alert is a multidisciplinary genetic and epidemiological study of Type II (non insulin-dependent) diabetes in Texas Mexican Americans. We report the anthropometry of 1,155 individuals 10 to 70 or more years with particular reference to overweight, fatness, and anatomical fat patterning in the sample. Children ages 10-18 of both sexes are growing at the 50th percentile of the reference data (U.S. Health and Nutrition Examination Survey-1) for height, Wt/Ht2, and triceps and subscapular skinfolds. Adults are well below median height but well above median Wt/Ht2 and skinfolds. Prevalence of obesity (Wt/Ht2 greater than or equal to 30) among adults is typically 30% or higher by age 30. Diabetics compared to age/sex-matched non diabetics have shorter sitting heights, have more upper body fat (subscapular skinfold), have less lower body fat (lateral calf skinfold), and were heavier at maximum weight and at age 18. The ratio of lower to upper body fat distribution decreases over the life cycle, being highest at adolescence and lowest at ages 40-50 in both sexes. Our results show a precipitous weight gain after maturity in the sample and an association of diabetes with differences in anatomical fat patterning. The age-related changes in fat patterning need to be explained in terms of their ecological and genetic influences.

Effects of spinal tractotomy on spatial sequence recognition in macaques

Five Macaca speciosa monkeys were trained to discriminate between the order of two tactile stimulus presentations (proximal-distal vs. distal-proximal) to the lateral calf. Psychophysical thresholds for tactile sequence recognition were obtained by varying the distance between the spots stimulated. Stabilized preoperative thresholds for stimulation on the lateral calf averaged 10.4 mm, which is comparable to point localization thresholds for sequential contact of the proximal limbs of humans. Complete interruption of the ipsilateral fasciculus gracilis produced elevations of thresholds within the first 3 postoperative weeks to an average of 3.6 times the control values. With training over 6 postoperative months, normal discrimination recovered. In contrast to the effects of dorsal column (DC) lesions, interruption of the lateral and ventral columns ipsilaterally or contralaterally produced no deficit or a mild and transient deficit. Monkeys with isolation of either the ipsilateral dorsolateral column (ILC) or the contralateral ventral quadrant (CVQ) exhibited substantial and enduring deficits. Thresholds were elevated an average of 5 times the control values, and recovery was not observed or was incomplete after months of training. In contrast, isolation of the ipsilateral dorsal column produced little or no threshold elevation. The results of isolating lesions complement the series of primary lesions to each cord sector, showing that spatiotactile sequence recognition for the hindlimb is served more critically by the dorsal columns than by the lateral columns.

12% Lactate Lotion for the Treatment of Xerosis

Sixty patients with moderate to severe xerosis participated in a 21-day, randomized, double-blind, contralateral study for efficacy of a specially neutralized 12% lactate lotion compared with a 5% lactic acid lotion and a nonlactated emollient lotion. The severity of xerosis was evaluated on days 0, 7, 14, and 21 during treatment and on days 28 and 35 one and two weeks after treatment was discontinued. All three preparations significantly reduced the severity scores of xerosis. During the "regression" period after treatment was discontinued, patients receiving 12% lactate lotion, compared with those treated with nonlactated emollient lotion, had had significantly greater reductions in the severity scores of xerosis for the lateral calf area at days 28 and 35 and for total severity scores (combined mean differences for lateral, medial, and pretibial areas) at day 35. Compared with 5% lactic acid lotion, the 12% lactate lotion provided significantly greater reductions for total severity scores at days 28 and 35.