Transmitter-operated channels in rabbit retinal astrocytes studied in situ by whole-cell patch clamping

Glutamate and GABA open ion channels in the membranes of astrocytes found on the vitreal surface of the rabbit retinal visual streak. The glutamate-operated channels are opened by kainate, quisqualate, and AMPA, but not by NMDA, aspartate, or the metabotropic agonist 1-aminocyclopentane-1 S,3R-dicarboxylic acid. The effects of glutamate and its analogs can be blocked by 20 microM 6-cyano-7-nitroquinoxaline-2,3-dione. The conductance increase evoked by 10 microM glutamate, a concentration of this transmitter near to that found in the vitreous humor that bathes these cells, was equivalent to 22% of the cell's resting conductance. The conductance increase evoked by 1 microM GABA, a concentration near that found in the vitreous, was equivalent to 131% of the cell's resting conductance. The effects of GABA can be blocked by bicuculline. These data show that GABA, and non-NMDA-type glutamate receptors play an important part in determining the resting potential of visual streak astrocytes in situ and that these channels may be of general importance for the functions of astrocytes in vivo.

Sequences of taxol and cisplatin: a phase I and pharmacologic study

Untreated and minimally pretreated solid tumor patients received alternating sequences of taxol and cisplatin. Sequential dose escalation of each agent using taxol doses of 110 or 135 mg/m2 and cisplatin doses of 50 or 75 mg/m2 resulted in four dosage permutations that induced grades 3 and 4 neutropenia in 72% to 84% and 50% to 53% of courses, respectively. Neutropenia was brief, and hospitalization for neutropenia and fever was required in 13% to 24% of courses. However, further escalation of taxol to 170 or 200 mg/m2 induced grade 4 neutropenia in 79% to 82% of courses. At the highest taxol-cisplatin dose level (200 mg/m2 to 75 mg/m2), the mean neutrophil count nadir was 98/microL, and hospitalization for neutropenia and fever was required in 64% of courses. The sequence of cisplatin before taxol, which has less antitumor activity in vitro, induced more profound neutropenia than the alternate sequence. Pharmacologic studies indicated that this difference was probably due to 25% lower taxol clearance rates when cisplatin preceded taxol. Although neurotoxicity was initially thought to be a potentially serious effect of the combination, mild to modest neurotoxicity occurred in only 27% of patients. Adverse effects also included myalgias, alopecia, vomiting, diarrhea, bradycardia, and asymptomatic ventricular tachycardia. Objective responses were noted in melanoma, as well as non-small-cell lung, ovarian, breast, head and neck, colon, and pancreatic carcinomas. Based on these results, the sequence of taxol before cisplatin at doses of 135 and 75 mg/m2, respectively, is recommended for phase II/III trials, with escalation of taxol to 170 mg/m2 if treatment is well tolerated.

Comparison of clinical, radionuclide, and radiographic features of osteoarthritis of the hands

Simultaneous clinical, scintigraphic, and macroradiographic assessments were carried out on 32 patients with hand osteoarthritis and the results at entry and one year reported. The presence and growth of osteophyte correlated with symptoms and a positive scan. The scan did not detect the radiographic features of juxta-articular radiolucencies, subchondral sclerosis, or cartilage thinning. Osteophytes, particularly when fast growing, produce pain, a 'hot' scan, and may predict disintegration of joint architecture.

Estrus induction in the bitch using a combination diethylstilbestrol and FSH-P

The purpose of the study was to induce estrus and ovulation in normal bitches using a combination of diethylstilbestrol (DES) and follicle stimulating hormone of porcine pituitary origin (FSH-P). Thirteen mature mongrel female dogs were divided into two groups, the first group was treated for estrus induction during late anestrus and the second group during mid-anestrus. The dogs were monitored by teasing, vaginal cytology, and hormonal assay during the induced (n=13) and the previous spontaneous estrous cycle (n=9). Six of eight and three of five bitches came into standing estrus in the first and second group, respectively. Of the bitches that came into estrus, three conceived in the first group and one in the second. The average induced litter size was 7.0 versus 7.5 for the colony. Based on vaginal cytology the induced proestrus and estrus lasted 1.7 (0 to 3) and 12.9 (4 to 24) d, respectively, while the spontaneous proestrus and estrus lasted 5.8 (0-17) and 12.8 (9-15) d, respectively. Progesterone profiles were similar between the induced and spontaneous estrous cycles, although the progesterone peak was higher during the spontaneous cycle. The preovulatory luteinizing hormone (LH) surge was observed in only one induced estrous cycle. Modest results were obtained with this therapy. However, the litter sizes were normal and the induced cycles were very similar to the physiologic ones. No side effects were seen with the oral form of DES.

Mentors and role models for women in academic medicine

Senior mentors and role models have a positive influence on the career advancement of junior professionals in law, business, and medicine. In medicine an increasing number of women are pursuing academic careers, but available senior mentors to provide career guidance are often lacking. We report on the results of a national survey of 558 full-time faculty women, aged 50 years and younger, in departments of medicine in the United States, regarding their experience with role models and mentors. Women with mentors report more publications and more time spent on research activity than those without mentors. Women with a role model reported higher overall career satisfaction. This report, with illustrative examples, may be helpful to other women pursuing academic careers and to physicians who serve as mentors or role models to others.

Toward a rational therapeutic strategy for arachnoiditis. A possible role for d-penicillamine

Twenty-six patients (13 men and 13 women), ranging in age from 38 to 75 years, with surgical and/or radiculographic evidence of chronic adhesive spinal arachnoiditis (CASA) were admitted to a randomly allocated, double-blind, 6-month crossover trial of d-penicillamine (500 mg/day) versus matching placebo. Assessments using subjective and objective criteria at 3-month intervals demonstrated no statistically significant effect with either d-penicillamine or placebo or between them. Thirteen of the 17 patients completing the trial expressed no clear preference. One patient preferred placebo. The remaining three patients who expressed strong preference for d-penicillamine (supported by objective data) subsequently maintained improvement on long-term therapy for up to 5 years. It is concluded that there may be a small subgroup of patients with CASA who might benefit from d-penicillamine therapy.

Congenital ossifying fibroma (osteofibrous dysplasia) of the tibia--a case report

Ossifying fibromas of the long bones of the leg are benign lesions occurring in the pediatric age group identical in histological appearance to the similarly named tumor of the jaw in adults. Most frequently presentation occurs after minor trauma with symptoms of a swelling of the tibia or fibula which may be painful. Pathological fracture or limp are also occasional presentations. Congenital cases are extremely rare. We describe an otherwise normal male neonate who presented at birth with a bowed right lower leg. The limb was 1 cm shorter than the other side, with tibia vara and a firm mass situated anteriorly. X-ray showed a mixed lytic and sclerotic lesion in the proximal metaphysis of the tibia. Biopsy showed collagenous stroma containing spindle cells and irregular trabeculae of woven bone rimmed by plump osteoblasts. As the appearances were typical of an ossifying fibroma (osteofibrous dysplasia) no surgical treatment was given. The patient was well with no growth of the tumor and with radiological evidence of healing at 1 year follow up. This case is presented to draw attention to the clinicopathological features of this unusual lesion which must be considered in the differential diagnosis of congenital lesions of the tibia.

Differential binding of P. aeruginosa and S. aureus to corneal epithelium in culture

Adherence of bacteria to corneal epithelium is a prerequisite for corneal infection. We used two methods to study the binding of Pseudomonas aeruginosa and Staphylococcus aureus to rabbit corneal epithelial cells in culture. In the first method, rabbit corneal epithelial cells grown on glass slides were incubated with P. aeruginosa or S. aureus (10(7) CFU/ml) at room temperature for 90 min, and the bacterial binding to the epithelial cells was examined by light microscopy. Both P. aeruginosa and S. aureus bound to epithelial cells. P. aeruginosa was bound to the cell periphery whereas S. aureus was bound randomly to the cell surface. In the second method, suspension cultures of corneal epithelial cells were used. In contrast to the findings in cultures on slides, binding pattern with cells in suspension was similar for both species and resembled that for S. aureus in cultures on slides. A much greater number of P. aeruginosa (186 +/- 11 bacteria/epithelial cell) than S. aureus (30 +/- 1.5 bacteria/epithelial cell) bound to epithelial cells grown on glass slides. In contrast, a similar number of P. aeruginosa (25 +/- 5.1) and S. aureus (20 +/- 4.7) bound to epithelial cells grown in suspension cultures. Using either method, Escherichia coli and Streptococcus pyogenes did not bind significantly (less than 5/cell) to corneal epithelial cells. The above methods should prove useful for characterization of bacterial binding to corneal epithelial cells in culture.

Quantitative microfocal radiographic assessment of progression in osteoarthritis of the hand

We studied 32 patients with osteoarthritis who had 5x macroradiographs taken of their wrists and hands at 6-month intervals over an 18-month period. The higher magnification and resolution of microfocal radiography permitted the quantitative detection of progressive changes in 4 different features: subchondral sclerosis, the number and size of osteophytes, juxtaarticular radiolucencies, and joint space narrowing. Compared with normal control subjects, subchondral cortical thickness was greater in all patients at entry and showed a variable degree of change over the study period. Osteophytes and juxtaarticular radiolucencies were present in all patients at study entry; by the end of the study, osteophytes had increased in number and area, and juxtaarticular radiolucencies had increased in area, but not in number. At entry, 44% of the patients had joint space narrowing significantly greater than that in the control subjects; by 18 months, this proportion increased to 65%. No correlation was found between subchondral sclerosis, osteophytes, juxtaarticular radiolucencies, and joint space narrowing. We conclude that in osteoarthritis of the hand, the bony changes have progressed significantly before the occurrence of radiographically evident joint space narrowing indicative of cartilage thinning.

Gene UL11 of herpes simplex virus type 1 encodes a virion protein which is myristylated

We have investigated whether herpes simplex virus (HSV) contains structural polypeptides which are modified by myristic acid. We demonstrate that herpes simplex virions contain a family of myristylated proteins, Mr approximately 13,000 to 16,000. These were mapped, using HSV-1/HSV-2 intertypic recombinants, to 0.130 to 0.204 map units on the virus genome. Using anti-peptide sera, raised against the carboxyterminus of the predicted UL11 gene product, we have established that the myristylated virion polypeptides are products of the viral gene UL11.

Protein-related abnormalities in keratoconus

Two-dimensional electrophoretic maps of extracts from eleven normal and eleven keratoconus corneas were compared. Of the eleven corneas analyzed, eight were pooled and the remaining three were analyzed individually. Several differences were demonstrated between electrophoretic patterns of normal and keratoconus corneas. In keratoconus corneas, 1) two abnormal components (MW 54kD and 26kD) were observed; 2) three normal corneal components (MW 12kD, 14kD, and 39kD) were present in significantly higher amounts; and 3) three normal corneal proteins (MW 66kD, 55kD, and 13kD) were present in reduced amounts. The molecular weight and isoelectric point of one of the normal corneal proteins that we found to be reduced in keratoconus corneas were close to that of a subunit of prolyl-4-hydroxylase, an enzyme required for hydroxylation of proline residues of collagen. The possibility the abnormal proteins detected in the keratoconus corneas were derived from those normal corneal proteins which were absent or were present in reduced amounts in the keratoconus corneas remains to be established. This study may provide protein markers for elucidation of the biochemical abnormality in keratoconus.

Surgical treatment of metatarsus adductus using a combined soft tissue and osseous approach

Children between 6 and 8 years of age with metatarsus adductus deformity have been considered to be in the gray zone for surgical correction. Should osseous or soft tissue procedures be implemented to reduce the adducted attitude of the metatarsals? The literature clearly describes one or the other and the intermediary chondrotomy procedure described by Johnson. The use of a combined approach has not been presented. The present authors offer a brief review of metatarsus adductus, and two case reports using a modified, combined approach. Two 7-year-old girls presented with bilateral resistant metatarsus adductus deformities. The authors contend that the first and fifth metatarsals are the major deforming forces in this age group, and may be corrected with base wedge osteotomies, while the central three metatarsals are more amendable to capsular and ligamentous releases. Advantages of soft tissue procedures on the central rays include avoidance of extensive dissection, creating less trauma and avoidance of the need for internal fixation. The obvious disadvantage is the inability to adequately reduce the deformity. This can be assessed intraoperatively. These authors, therefore, conclude that this modified surgical approach is a viable alternative to the previously described procedures for resistant metatarsus adductus.

Biological function of the rotavirus protein VP4: observations on porcine isolates from China

Rotaviruses isolated from pigs in China were grown in MA104 cells. One tissue-culture-adapted isolate consisted of two subpopulations (variants), the RNA profiles of which differed in the relative migration of RNA segment 4 only. The variants were separated by plaque purification and by recovery from limiting dilutions and remained genetically stable. The variant possessing the slower migrating RNA segment 4, called 4S, grew faster and formed large plaques after 4-6 days incubation, whereas the variant possessing the faster migrating RNA segment 4, called 4F, grew more slowly and formed only microscopic plaques after 10-14 days incubation. The protein product of the 4F RNA occurred in much lower concentration in infected cells than the product of the 4S RNA. The RNA segments 4 of the two variants were found to be closely related when tested by dot hybridization under stringent conditions. The 4S RNA is more resistant to denaturation with methyl mercuric hydroxide than is the 4F RNA. The relevance of these findings to the biological functions of rotaviruses is discussed.

Clinicopathological and radiological features of two cases of intraventricular meningioma in childhood

The clinical, radiological and pathological features of two cases of intraventricular meningioma in a 9-year-old boy and a 9-year-old girl are reported. Presenting features included headache, vomiting and somnolence with no localizing neurological signs on physical examination. Neither patient showed evidence of neurofibromatosis. CT scans were helpful in establishing the preoperative diagnoses with uniformly hyperdense, well-circumscribed lesions showing bright enhancement after contrast within the lateral and third ventricles respectively. Histological examination revealed mixed fibroblastic/angioblastic and fibroblastic patterns, with typical electron-microscopic and immunohistochemical features of meningioma. Successful surgical removal was achieved in both cases.

Attitudes, social choices and substance use

This research investigated the effects of four conditions on attitudes and social choices regarding substance use, i.e., involvement with smoking, drinking, and drugs. Three conditions, the treatment dimension, consisted of the presentation of negative evaluations, legal consequences, and physical consequences of substance use, and the remaining condition, a stratification variable, comprised the social reasoning ability of the subjects. The data, produced by 160 students in the 4th and 11th grades, were analyzed in a repeated-measures design which included the treatments, stratification, and the repeated variable, retention. The results indicated, generally, that young children's attitudes and social choices were more negative than those of adolescents and also showed greater resistance to change. Surprisingly, legal threats to drinking produced greater positive attitudes toward drinking among adolescents and were more effective than physical punishment in this respect for all students. Of importance was the outcome that over time, all students made more favorable social choices for substance use with the exception that young children's social choices for drinking remained negative. Because of the significant interactions which occurred, many of the results can be explained in terms of differences in both social reasoning ability and developmental levels. Implications for practitioners and researchers are discussed.

Dwyer osteotomy for treatment of calcaneal varus

Treatment of varus deformity of the rearfoot is satisfactorily corrected with a lateral closing wedge osteotomy of the calcaneus. Whether the condition being treated is club foot, pes cavus deformity, or calcaneal varus alone, statistics show the varus component is consistently resolved with this osteotomy approach. A case report of calcaneal varus is presented, including a postoperative complication with resolution.

Myristylation of rotavirus proteins

After labelling with [3H]myristic acid during replication the structural proteins VP6 and VP2 of purified rotavirus particles were found to be myristylated in an amide bond. [3H]Palmitic acid was converted to myristic acid before bonding to the viral proteins. Possible functions of rotavirus protein myristylation are discussed.