Effect of lindane on clutch size and level of egg yolk protein in domestic duck

Lindane (gamma-hexachlorocyclohexane) was administered to laying ducks (Anas platyrhynchos domesticus) in 3 doses viz. (1) 20 mg/kg body weight daily, (2) 20 mg/kg body weight thrice weekly and (3) 20 mg/kg body weight twice weekly for 8 weeks. Egg laying was immediately stopped for 3 weeks in the first 2 groups and when resumed it became highly irregular with clutch size drastically reduced (1 against 7 of control ducks). The initial delay was absent in the 3rd group and reduction in clutch size was also marginal (5 against 7). Laying frequencies were 8.3%, 11.7% and 40% in Groups 1, 2 and 3 birds respectively against 50% frequency of the normal ducks. Hepatic, plasma and ovarian vitellogenin levels were substantially reduced in the first 2 groups. At the same time liver RNA level was markedly reduced. Ovary of such birds lack mature vitellogenic follicles and the thecal layer of moderately differentiated oocytes became highly atrophic. Stilbestrol (50 mg/kg body wt--single injection) administration to lindane fed pauci-layer ducks restored egg laying within 24 h, with return of a normal level of plasma vitellogenin and hepatic RNA. The results suggest that lindane induced estradiol insufficiency causes inhibition of hepatic RNA and yolk protein synthesis, thereby preventing transformation of moderately differentiated oocytes to mature vitellogenic follicles, delaying ovulation and thus drastically reducing clutch size.

Flow in arteries in the presence of stenosis

Of concern in the paper is a study of blood flow in an arterial segment having a stenosis. The artery is modelled as an initially stressed orthotropic elastic tube filled with a viscous incompressible fluid. The analysis is based on the assumption of the presence of a mild stenosis in the artery. Blood is treated as a Newtonian fluid. The effect of the surrounding connective tissues on the motion of the wall has been incorporated. Propagation of small amplitude harmonic waves, generated due to the flow of blood where the wave length is large compared to the radius of the arterial segment, is is considered in detail.

Effect of lindane on cytology and cytochemistry of exfoliated vaginal cells

Intraperitoneal injection of 5 mg or 10 mg per kg body weight of technical grade lindane twice weekly in Charles-Foster female rats induced marked disturbance of the estrous cycle, prolonging the proestrus phase considerably (5-7 times more compared to the normal) and thereby delaying ovulation. Exfoliated cells at proestrus are marked by high concentrations of glycogen, SDH and alkaline phosphatase while estrus is characterized by increased activity of acid phosphatase and mucopolysaccharides. Corresponding changes in the polysaccharides concentrations and enzyme activities of the exfoliated cells seen in the lindane treated rats were well correlated with disturbances of the cycle. The data suggest that lindane exerts an estrogen-like effect by inducing a temporary negative feedback on pituitary gonadotropin secretion.

A study of rotational brain injury

Of concern in the paper is an investigation on brain injuries which may occur owing to an input angular acceleration of the head. The study is based on the use of an improved mathematical model for the cranium. The eccentricity of the braincase is incorporated through the consideration of a prolate spheroidal shell as the representative of the skull. Also the dissipative mechanical behaviour of the brain material (as per the observations of experimenters) has been accounted for by considering the material contained in the shell as viscoelastic. The problem is formulated in terms of prolate spheroidal coordinates. The singularities of the governing equations of motion (when expressed in the prolate coordinate system) are removed by a suitable transformation of the concerned dependent variable, viz. the one that stands for the angular displacement of a representative point of the system. In the first place the solution of the boundary value problem is sought in the Laplace transform space, by employing a finite difference technique. Use of the alternating-direction-implicit method together with Thomas algorithm was made for obtaining the angular acceleration in the transformed space. The Laplace inversion is also carried out with the help of numerical procedures (Gauss quadrature formula is used for this purpose). The results of the parametric study are presented through graphs. The plots illustrate the shear stresses and strains in the brain medium. A meaningful comparison of the computational results with those of previous investigations indicate that the eccentricity of the braincase plays a significant role in causing injury to the brain.

Dynamic response of arterial walls in vivo

By the use of non-linear constitutive equations suitable for the characterization of anisotropic viscoelastic incompressible materials under finite deformations, the paper is devoted to analytical study on the dynamic stress field in arterial walls under the combined action of the pressure of blood on the inner surface and the pressure from the neighbouring components of the body on the outer surface. By using short time range approximations, the magnitudes of the radial and circumferential stresses are examined at various locations of the vascular wall and for different time intervals. It is observed that consideration of the mechanical influence of the external tissues and the inertial forces makes the derived stress field quite close to the experimental results reported recently by Fung et al. (1979), in comparison to the results of Cheung et al. (1972), who did not consider the aforementioned factors. It can thus be concluded that these factors need be considered for the studies of the stress field in arteries in vivo.

A free-vibration analysis for the human cranial system

The problem of free-vibration of the cranial vault is studied in the paper by taking into account the dissipative material behaviour of both the skull and the brain. Two mathematical models are considered for this purpose. In one model, the layered structure (inner table, diploë and outer table) of the skull is considered, the outer surface of the skull being assumed to be traction-free while the second model assumes the homogeneity of the skull but takes into account the mechanical influence of the scalp. Results of numerical computation show that the dissipative material behaviour of the skull as well as the brain and also the mechanical influence of the scalp have a significant effect on the frequency spectrum of the freely vibrating cranial system.

Congenital absence of superior vena cava: unusual anomaly of superior systemic veins complicating pacemaker placement

Congenital anomalies of the superior systemic veins can complicate placement of transvenous pacemaker electrode leads. Persistent left superior vena cava is the most common congenital anomaly; in this paper, we describe the case of a patient who had congenital absence of both superior venae cavae, which has not been reported previously. The superior systemic veins drained into persistent double azygos veins subdiaphragmatically. The anomaly was verified by venography. Temporary cardiac pacing was established by passing the electrode lead through the femoral vein, and a permanent epicardial pacemaker lead was placed thereafter. This appears to be the first recorded case of such an anomaly.

Systolic time intervals (STI) as indicators of myocardial thyroid hormone effect. A correlative study in hypothyroid and hyperthyroid patients

Systolic time intervals consisting of indices of electromechanical systole (QS2-I), left ventricular ejection time (LVET-I) and pre-ejection period (PEP-I) were calculated serially during therapy in 12 euthyroid, 9 hypothyroid and 9 hyperthyroid individuals. These parameters were analyzed sequentially together with the changes in serum thyroxine (T4), triiodothyronine (T3) and thyrotrophin (TSH) in order to determine the sensitivity of these non-invasive procedures in monitoring peripheral thyroid hormone effect. The results are expreseed in mean ± sem. QS2-I (506.3 ± 8.2 ms) and PEP-I (102.9 ± 4.2) were shortened (P < 0.02 and P < 0.001, respectively) in hyperthyroidism and prolonged (579.3 ± 7.3 and 169.6 ± 3.6 ms) in hypothyroidism (P < 0.01 and P < 0.001, respectively) compared to euthyroid controls (538.1 ± 8.8 and 130.3 ± 5.3 ms), while LVET-I did not change significantly in either condition. Simultaneous determinations of circulating T4, T3 and TSH showed changes appropriate to both hypo- and hyperthyroid states. In 2 patients with T3-thyrotoxicosis, PEP-I was decreased to an average of 103.1 ms, while in 2 patients with compensated hypothyroidism (normal T4 but elevated TSH) this was prolonged to 163.7 ms (average) compared to euthyroid controls. During treatment the hypothyroid group showed significant sequential correlation of TSH and PEP-I. In the hyperthyroid individuals, PEP-I correlated significantly with T4 and T3. PEP-I may be a useful, sensitive, quantitative biologic indicator of thyroid hormone effect on myocardial function.

Late evaluation of patients undergoing valve replacement with the Björk-Shiley prosthesis

This study analyzes 484 patients who survived mitral, aortic, or mitral and aortic valve replacement using the Björk-Shiley prosthesis from January, 1970, through December 31, 1974. Long-term follow-up of 1 1/2 to 6 1/2 years (mean, 3.67 yr) was done on 435 patients (98.2%). Eighty to 85% of the patients have improved noticeably. Thromboembolic problems occurred in 6.9%, representing 1.5 emboli per 1,000 patient-months. Anticoagulant bleeding problems occurred in 6.4% of the patients; late mortality was 15%. Actuarial survival curves showed patients at risk to 6 years having a 79% chance of survival. The same analysis according to preoperative New York Heart Association Functional Classification showed a striking reduction in survival in class IV patients. The Björk-Shiley prosthesis is a good choice for valve replacement today. Earlier diagnosis and treatment are needed to obtain better long-term survival.

Gait study in evaluation of results in intramedullary nailing for femoral shaft fractures

The present preliminary investigation conducted on six adult males whose femur shaft fractures had been fixed internally by means of Hansen-Street intermedullary nails indicated that our gait study technic helps confirm the clinical findings in such cases. Five patients, although their fractures had united and they had resumed their usual activities, were not deemed quite normal as yet and the causes for their gait abnormality were identified in the clinical examination. The gait study technic thus provided fairly accurate quantitative support of the clinical findings.

A novel spray reagent for phospholipid detection

Ammonium pentachlorooxomolybdate in a solution of 7-9 N H2SO4 was found to be an excellent spray reagent for the specific detection of phospholipids on thin-layer chromatograms. It is better than the usual molybdenum blue reagent due to its greater sensitivity and its ability to eliminate the problem of the development of background blue color on prolonged exposure.