An inexpensive microdrive for chronic single-unit recording

A microdrive and microelectrode costing about $2.67 is described. The assembly is lightweight, compact, and versatile and is ideal for chronic single-unit recording from behaving rats. It is easy to assemble and operate and has been used successfully by undergraduates in the teaching and research laboratory.

Mesothelioma mortality among former asbestos-cement workers in Israel, 1953-90

Asbestos workers have long been recognized as a high risk group for the development of mesothelioma and other cancers. In this study we collated from a variety of sources 26 mesothelioma deaths that occurred between 1978 and 1990 among a cohort of some 4,441 former workers from an asbestos-cement plant in northern Israel. Since the expected number of deaths for this number of Israeli males in this age-group over this period is 0.12 cases, the risk of this disease was more than 223 times the national rate, age and sex adjusted [standardized mortality ratio (SMR) = 22,351, P < 0.001]. The mean years of exposure of persons who died from mesothelioma was 16.2 (SE 2.5). The mean latency period for mesothelioma cases from onset of exposure to death was 25.6 years (SE 1.3). Additional follow-up systems are needed to ensure complete reporting of asbestos-related diseases, including epidemiologic follow-up of asbestos-exposed workers after cessation of their work, with regular analysis of death and cancer registry data for high risk groups. Asbestos-related cancer is an important element in cancer epidemiology that requires further development in Israel. Studies of former workers, their families and of persons who worked or attended school adjacent to the asbestos-cement factory, as well as follow-up of other former worker groups exposed to asbestos are recommended.

Motion sickness-like syndrome among tank simulator drivers

A military tank driving simulator has recently been introduced as a training aid for tank drivers in the Israel Defense Forces. Reports of nausea and vomiting among the first users of the simulator launched our investigation of the possible existence of a motion sickness-like syndrome among simulator drivers. Although the 59 subjects drove the simulator without any report of vomiting, other motion sickness-like symptoms were frequently reported. A comparison of symptoms reported after simulator and real tank driving show that dizziness, nausea, disorientation and hypersalivation were more frequently reported by simulator drivers and were of greater intensity. However, sweating and drowsiness were more prevalent among real tank drivers. The objective effect of driving the simulator was evaluated by instability and performance tests that were conducted before, during and after driving the simulator. A greater decrement in test results was observed among subjects reporting higher frequency of motion sickness-like symptoms.

Combined ovarian vein catheterization with ovarian stimulation in the diagnosis of androgen overproduction

A 28-year-old woman was evaluated for late onset secondary amenorrhea, progressive hirsutism and an elevated serum testosterone concentration. Her serum cortisol, androstenedione, dehydroepiandrosterone sulfate and 17-hydroxyprogesterone levels were normal. Bilateral ovarian and adrenal vein catheterization demonstrated mild elevated testosterone and androstenedione levels in the right ovarian vein. Fifteen minutes after administering the intravenous injection of 5,000 IU human chorionic gonadotropin, there was a six and a half to sevenfold increase in the level of these two hormones in the right ovarian vein with no significant change in hormone levels from other sources. Based on the ovarian peripheral vein gradients obtained during venography following ovarian stimulation, the diagnosis of right ovarian hyperthecosis was made. This diagnosis could not have been reached without the combination of selective ovarian vein catheterization and ovarian stimulation. We recommend that this combined test, which may provide additional information on the source of the androgens in women with hyperandrogens, be performed in selected cases, when a virilizing tumor is suspected.

Design and immunological properties of topographic immunogenic determinants of a protein antigen (LDH-C4) as vaccines

Antibodies elicited by immunization with short peptides containing antigenic determinants have been shown, in general, to bind with greatly reduced affinity to the corresponding region in the native proteins. Thus, contiguous linear peptides have not proven to be effective immunogens in generating high affinity neutralizing or protective antibodies and consequently appear to be poor prospects for vaccines. The molecular basis for such reduced reactivity is clear from the crystal structure determination of antibody Fabs bound to protein antigens, which showed the complementarity between interfaces to be lock-and-key-like and extending over a large area (750 A2) involving discontinuous segments of the polypeptide chain. Thus, small perturbations in the secondary and tertiary structure of the antigen have profound effects on the fit of the antigen and its corresponding antibody. Because short peptides are unlikely to assume any particular conformation in solution, the fit is likely to be poor. New strategies are therefore required to produce conformationally stable peptides that mimic the critical structural features of the protein antigenic site. Here we show that a putative topographic determinant of the testis-specific isozyme of lactate dehydrogenase C4 (LDH-C4), designed and synthesized to adopt a well defined alpha-helical secondary and tertiary structure (four-helix bundle motif) in aqueous solutions, is highly immunogenic in both rabbits and mice, inducing IgG antibodies that bind to native LDH-C4. This engineered conformational 40-residue peptide is considerably more effective in inducing antibodies, as compared with the corresponding linear peptide. The antibody response is obtained without coupling the peptide to a carrier protein, suggesting that the peptide contains a T-cell antigenic determinant. The strategy described here to produce a conformationally stable peptide that mimics the native structure may have general applications in vaccine design.

Associations between sexual experiences and fantasies in a nonpatient population: a preliminary study

We have been interested in devising some methodology short of psychoanalytic therapy to study the relationship of conscious fantasy to personality trends and behavior. Presented here is a pilot study, utilizing the questionnaire technique, the sample consisting of 193 students enrolled at one prestigious urban university, that reports on the prevalence and content of conscious sexual fantasies in a normal (nonpatient) population and their relationship to sexual behaviors. Factor analysis suggested four experience and four fantasy clusters. Those individuals who score high on one experience factor are apt to score high on all other experience factors as well. The same is true of the fantasy factors. Our findings indicate that low sexual activity and low levels of sexual fantasy go together, whereas more sexual experience is connected to a greater range of sexual fantasy. Consequently, erotic fantasies cannot be viewed as compensation for lack of sexual outlet. Instead, there is a positive correlation between the two domains of sexual fantasies and sexual behaviors. Our overall results lead us to conclude that by and large, people are sexual generalists not specialists.

Hypertrophic obstructive cardiomyopathy presenting with profound hypotension. Role of two-dimensional and Doppler echocardiography in diagnosis and management

Five patients, all women, age ranges 59 to 84 years, with underlying hypertrophic obstructive cardiomyopathy (HOCM) presented with profound hypotension. Initial clinical and hemodynamic evaluation suggested cardiogenic shock in two cases, acute myocardial ischemia in two cases, and hypovolemia in one case. The two patients thought to be in cardiogenic shock were given inotropes without improvement. One patient in whom myocardial ischemia was suspected received nitroglycerin, followed by a marked fall in blood pressure. All five patients remained hypotensive until two-dimensional and Doppler echocardiography were performed, identifying HOCM as the cause of the hypotension, thereby allowing for corrective therapeutic measures.

Protein turnover and resting energy expenditure in patients with undernutrition and chronic lung disease

Whole-body protein metabolism was studied in 11 undernourished cystic fibrosis (CF) patient (7 female), 12 normally nourished CF patients (3 female), 7 anorexia nervosa (AN) patients (all female), and 15 normal control subjects (9 female). Protein turnover was studied by the single dose [15N]glycine method and the cumulative excretion of labeled urinary urea and ammonia. Energy metabolism was studied by open-circuit indirect calorimetry. Contrary to previous reports, no differences were found between the protein turnover of CF groups and the normal control group. However, patients with AN had a negative net protein deposition. Resting energy expenditure was significantly reduced in AN patients and increased in CF patients. The gender of CF patients did not affect protein and energy metabolism but fat mass was higher and fat-free mass was lower in CF females.

Transperineal ultrasound examination in the evaluation of prostatic size

Eighty patients with benign prostatic hyperplasia underwent transperineal ultrasonographic evaluation of prostatic size and calculation of prostatic volume. In 10 patients transabdominal prostatic ultrasonography was also performed and the findings compared with those of transperineal examination. The estimated prostatic volume measured by transperineal ultrasonography was compared to the actual weight of the surgically removed gland. The correlation coefficient was 0.89 (P less than 0.0001). The transperineal and transabdominal ultrasonographic estimated volumes were also compared. The correlation coefficient was 0.92 (P less than 0.0001). No pain or discomfort were reported by the patients. Transperineal ultrasonography appears to be an accurate, fast and easy method to evaluate prostatic volume.

Effect of refeeding on the energy metabolism of adolescent girls who have anorexia nervosa

The effect of refeeding on resting energy expenditure (REE) and substrate utilization was studied in 18 hospitalized adolescent girls (aged 12.9-19.1 years) suffering from anorexia nervosa. Changes in body composition were monitored weekly and included weight, fat body mass (FBM), lean body mass (LBM) and total body potassium (TBK). REE was studied weekly by open-circuit calorimetry. Weight gain was noted in all patients (38.2 +/- 5.6 to 44.5 +/- 5.3 kg), involving increased FBM and LBM. REE increased per kg of weight (91.6 +/- 15.1 to 101.7 +/- 18.0 kJ kg-1 d-1) and LBM over the first weeks of refeeding (P less than 0.025) and then stabilized. Substrate utilization showed an increase in carbohydrate and protein utilization (P less than 0.001) during the first few weeks of refeeding. We also studied the thermic effect of food (TEF) in 14 of the 18 subjects. Upon admission the subjects had a reduced TEF (36.4 +/- 24.3 kJ 2 h-1) (P less than 0.001). With refeeding TEF rose to a peak or plateau, then decreased to normal levels (61.9 +/- 36.0 kJ 2 h-1) before discharge from hospital. We conclude that the energy metabolism of adolescent girls adapts to semi-starvation by a reduction in both REE and TEF; with refeeding there is reversal of this adaptive function.

DNA methylation and expression of the genes coding for lactate dehydrogenases A and C during rodent spermatogenesis

The testis chromatin undergoes profound structural alterations and functional changes during spermatogenesis. Changes in DNA methylation have been correlated with gene expression in a number of systems, but the relationship between methylation and gene expression for testicular genes is unclear. To address this question, DNA methylation patterns and mRNA expression for a somatic form of lactate dehydrogenase (LDH), LDH-A, were compared with those of the testis-specific form, LDH-C, in preparations from testes of prepubertal and sexually mature mice, from isolated testicular cells, and from somatic tissues. At specific sites, LDH-A was less methylated in adult testis than in spleen DNA; the decreased methylation in the testicular DNA occurred as early as type A spermatogonia. In contrast, DNA methylation patterns for LDH-C did not differ between spleen and testis DNAs. In Northern blots, the levels of LDH-A transcripts were low in total testis RNA obtained from 6-12-day-old mice, and in type A and B spermatogonia from 8-day-old mice. LDH-A mRNA levels increased gradually in testes from 16-45-day-old mice. LDH-C transcripts were first detectable in the testes of 12-day-old mice and increased as spermatogenesis proceeded. Both LDH-A and LDH-C mRNA levels were low in preleptotene spermatocytes and leptotene/zygotene spermatocytes and increased substantially in pachytene spermatocytes and round spermatids. Reduced levels of LDH-A and LDH-C mRNAs were found in the residual bodies/cytoplasts fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B and human immunodeficiency virus infection in street youths in Toronto, Canada

Hepatitis B and human immunodeficiency virus are transmitted by venereal contact or by the sharing of used needles during drug use. A questionnaire was administered to street youths admitting to prostitution and to a group denying prostitution, as well as to sexually active adolescents who lived with their family and were attending an adolescent medical clinic. The age, gender, race, number of sexual partners, condom use, illicit drug use, anal intercourse and admission to prostitution were recorded for each of the subjects. Serology was obtained for hepatitis B markers and human immunodeficiency virus antibody. Multiple regression analysis was performed to determine the factors which might predict hepatitis B serologic status. A single subject, who admitted to prostitution, was found to be human immunodeficiency virus-seropositive. Seven of 43 (16%) admitted prostitutes compared with 1 of 44 (2%) other street youth and none of 27 controls demonstrated anti-hepatitis B surface antibodies. The higher rate of seropositivity in admitted prostitutes was statistically significant (P less than 0.0097). Two seropositive prostitutes had IgM hepatitis B core antibody suggesting recent infection. Two factors, number of partners (P less than 0.0007) and practice of anal intercourse (P less than 0.05), were identified in the multiple regression analysis as predictive of seropositivity. Thus adolescents who live on the street are at increased risk for becoming infected with hepatitis B virus. The difficulty in ensuring vaccine coverage in this population would support calls for including hepatitis B vaccination as part of childhood immunization.

Rapid desalting of ammonium sulfate solutions by hydrophobic interaction chromatography

Open-air hydrophobic interaction chromatography with alkyl carbon functional groups coupled to agarose beads has been used to desalt large volumes of ammonium sulfate-fractionated bacterial cell lysates. The protein of interest can be simultaneously desalted and concentrated in less than 4 h, and the yield is significantly better than that obtained by the standard technique of precipitation, centrifugation, and dialysis.

Immunization of male but not female mice with the sperm-specific isozyme of lactate dehydrogenase (LDH-C4) impairs fertilization in vivo

The goals of this study were to determine the site at which fertility is impaired in mice immunized with LDH-C4 and to determine whether immunization of both males and females would have a greater antifertility effect than immunization of one sex alone. Mice were immunized with LDH-C4 in two systemic doses in Freund's adjuvants and two gastric doses in bicarbonate buffer. The presence of anti-LDH-C4 antibodies in uterine fluid was confirmed. Male and female mice were assigned to four blocks in which either the males, the females, both, or neither were immunized. Oviducts were viewed directly 1 h after mating for the presence of sperm. No significant effect of immunization on sperm transport to the oviduct could be demonstrated. Fertilization was evaluated 4 h after mating. It was found that immunization of males, but not females, impaired fertilization (19.6% versus 50.8% of the oocytes penetrated in 17 and 19 females, respectively). Orchitis was found histologically in 43.8% of the immunized males and 10% of the control males.

Associative agnosias and the functions of the left hemisphere

Associative agnosias are traditionally regarded as perceptual, and ideational apraxia as motor, deficits, but they can be understood as amnesias for generic knowledge, caused by bilateral or unilateral left-hemispheric cortical lesions. Current theories of hemispheric specialization explain these syndromes' mandatory link with left-hemispheric damage, and are validated by this link. This link reflects the multiple nature of generic, categorical representational systems, not all reducible to natural language, and the left hemisphere's principal role as their substrate, regardless of their dependence on language. The distinction between processing novel information, and processing based on well-established, routinized representations, captures a fundamental difference between the functions of the right and left hemispheres. The complementary link of apperceptive agnosias with right-and associative agnosias with left-hemisphere lesions is an expression of this general principle in the posterior cortex. Future studies of the neuroanatomy of agnosias in animals may offer insights into the evolutionary continuities of hemispheric specialization.

IQ patterns in affective disorder, lateralized and diffuse brain damage

Meta-analysis of 38 studies compared Wechsler IQ scores in affective disorder (A), lateralized right (RH), left (LH) and bilateral/diffuse (BI) brain damage. A, RH, and BI had lower PIQ than VIQ. In A and BI groups the PIQ/VIQ ratio was identical, whereas each differed significantly from the RH group which revealed a much lower PIQ/VIQ ratio. Similarity of neuropsychological profiles of A and RH patients is often interpreted as indicating predominant right-hemisphere involvement in affective disorder. The present findings suggest an alternative interpretation is possible: i.e., the presence of bilateral/diffuse CNS involvement in affective disorder. We do not believe that our findings strongly support one interpretation over the other. In future research, both possibilities should be considered.

Synthesis and biophysical characterization of engineered topographic immunogenic determinants with alpha alpha topology

Model peptides with predetermined secondary, tertiary, and quaternary conformation have been successfully designed, synthesized, and characterized in an attempt to mimic the three-dimensional structure of an antigenic determinant. This work is a continuing effort to map the antigenic structure of the protein antigen lactate dehydrogenase C4 (LDH-C4) to develop a contraceptive vaccine. A putative topographic determinant with alpha alpha topology which associates into four-helix bundles was designed on the basis of the framework model of protein folding. An idealized amphiphilic 18-residue sequence (alpha 1) and a 40-residue alpha alpha fold (alpha 3) have been shown to form stable 4-helix structures in solution with a free energy of association on the order of -20.8 kcal/mol (tetramerization of alpha 1) and -7.8 kcal/mol (dimerization of alpha 3). Both alpha 1 and alpha 3 form stable monolayers at the air-water interface. The CD spectra of Langmuir-Blodgett monolayers are characteristically alpha-helical. Both CD and FTIR spectroscopic studies reval a high degree of secondary structure. The SAXS data strongly suggest that the helices are arranged in a four-helix bundle since the radius of gyration of 17.2 A and the vector distribution function are indicative of a prolate ellipsoid of axial dimensions and molecular weight appropriate for the four-helix bundle. The major contribution to the formation and stabilization of alpha 1 and alpha 3 is believed to be hydrophobic interaction between the amphiphilic alpha-helices. The displayed heptad repeat, helix dipole, ion pairs, and the loop sequence may have also contributed to the overall stability and antiparallel packing of the helices. A detailed structural analysis of a relevant topographic immunogenic determinant will elucidate the nature of antigen-antibody interactions as well as provide insight into protein folding intermediates.

Retrograde amnesia following unilateral temporal lobectomy

Remote memory performance was assessed in a carefully matched sample of temporal lobectomy subjects and normal controls. Left temporal lobectomy subjects exhibited a consistent pattern of remote memory disturbance. Right temporal lobectomy subjects performed at the same level as normal controls. The pattern of impairment observed in left temporal lobectomy subjects was characterized by deficits in recall of chronological information from the past decade and extended to deficits in recall in some aspects of factual knowledge. The disorder could not be attributed solely to language deficits and was at least as severe as accompanying deficits in recent memory. These findings suggest that the left medial temporal region may play a significant role in recall of remote information in addition to its role in recent memory functions.

A reticulo-frontal disconnection syndrome

Persistent executive deficit, usually seen following prefrontal damage, is reported in a patient recovering from head trauma. Repeated neuroradidological examinations failed to reveal a lesion within the frontal lobes, but a circumscribed lesion in the ventral mesencephalic tegmentum was found. It is proposed that the observed syndrome was caused by damage to mesencephalic reticular nuclei and their projections into prefrontal cortex. The concept of a "reticulo-frontal disconnection syndrome" is introduced and its possible role in head trauma and schizophrenia discussed.

Gradiental approach to neocortical functional organization

Examination of neuropsychological syndromes suggests strong congruence between neuroanatomical and functional neocortical metrics. Two cortical syndromes disrupt cognitively close functions if and only if their neuroanatomical territories are close. To capture this relationship, the concept of a cognitive gradient is introduced as a basic unit of macroscopic neocortical brain-behavioral analysis. A cognitive gradient is a continuous distribution of related functions along an axis defined at its extremes by a pair of sensory projection or motor areas. Cortical gradiental structure is viewed as a fundamental symmetric organization on which hemispheric elaborations are superimposed. The gradiental structure of the left hemisphere is presented in detail as an illustration of the concept. It is presumed that a similar set of elaborations can be uncovered for the right hemisphere. The gradiental model implies that at least from the macroscopic standpoint, functional neocortical organization is to a substantial degree continuous, interactive, and emergent, as opposed to mosaic, modular, and prededicated. It is proposed that a shift from latter to former properties signified a major development in the evolution of the brain. Thalamo-cortical integration may represent coexistence of evolutionally early and recent principles of cerebral organization.

Regional localization of the sperm-specific lactate dehydrogenase, LDHC, gene on human chromosome 11

A cDNA clone complementary to the mRNA encoding the sperm-specific lactate dehydrogenase, LDHC, has been used to map the LDHC locus to the short arm of human chromosome 11. In situ hybridization data and analysis of mouse/human somatic cell hybrids carrying deletions of human chromosome 11 suggest that the gene is localized at p15.3-p15.5 close to the LDHA gene.