Kosambi-Cartan-Chern perspective on chaos: Unveiling hidden attractors in nonlinear autonomous systems

This article confronts the formidable task of exploring chaos within hidden attractors in nonlinear three-dimensional autonomous systems, highlighting the lack of established analytical and numerical methodologies for such investigations. As the basin of attraction does not touch the unstable manifold, there are no straightforward numerical processes to detect those attractors and one has to implement special numerical and analytical strategies. In this article we present an alternative approach that allows us to predict the basin of attraction associated with hidden attractors, overcoming the existing limitations. The method discussed here is based on the Kosambi-Cartan-Chern theory which enables us to conduct a comprehensive theoretical analysis by means of evaluating geometric invariants and instability exponents, thereby delineating the regions encompassing chaotic and periodic zones. Our analytical predictions are thoroughly validated by numerical results.

Limberg Flap in Pilonidal Sinus: Experience in Shaheed Suhrawardy Medical College Hospital

Pilonidal sinus disease is a common anorectal condition usually seen in young adult patients. Various methods have been described over the years and there is ongoing debate regarding the ideal method. This study was conducted to evaluate the advantages, results of rhomboid excision and Limberg flap reconstruction in the management of sacrococcygeal pilonidal sinus disease. This cross-sectional study was conducted in Surgery Unit-I of Department of Surgery, Shaheed Suhrawardy Medical College Hospital, Dhaka, Bangladesh a tertiary care centre from July 2016 to November 2017. It includes 19 patients who were treated for sacrococcygeal pilonidal sinus disease by Limberg (Rhomboid) flap. All patients that underwent the procedure had good postoperative outcome with minimal postoperative discomfort and were discharged in 3-4 days. There were 3 cases with complications. Limberg flap coverage is very effective for pilonidal disease with low complication rates, reduced hospital stay, low recurrence rates, earlier healing and shorter time off-work. This technique can be easily mastered and used as an indispensable tool for treating sacrococcygeal pilonidal sinus disease.

Measuring Sensitivity, Specificity and Accuracy of HRCT of Chest and Comparison with Biomarkers in COVID-19 Suspected Patients: A Cross Sectional Study

COVID-19 is a declared pandemic by World Health Organization. The diagnostic tests are not of high specificity and sensitivity, so far. Pro-inflammatory biomarkers and High Resolution Computed Tomography (HRCT) of chest are the common investigations performed to evaluate the diagnosis and prognosis of COVID-19. The objective of this study was to estimate the sensitivity, specificity and accuracy of HRCT and to find out the relationship between the biomarkers and HRCT findings. This was a cross-sectional descriptive study carried out in the COVID-19 suspected isolation unit of a tertiary hospital from July 2020 to November of 2020. Data were collected from electronic medical record (EMR). Relationship test were done by t-test and one-way-ANOVA test. Total 123 cases were enrolled after matching with selection criterion. Mean age of male was 62.5 years and female 57.7 years. Highest frequency of participants was observed in the 60-69 year age group. According to HRCT% findings 4 groups were made. They are below 25%, 25%-50%, 51%-75% and 76%-100%. The distribution of case among these groups was 15%, 44%, 35% and 6% respectively. The relationship between biomarkers (NLR, D-dimer, Ferritin and CRP) and HRCT% was found significant (p<0.05). In HRCT 92.5% lesion were peripherally placed and 99.2% cases were affected by both lungs. The sensitivity and specificity of HRCT were found 46% and 72.6% respectively with 62% accuracy. Raised biomarkers are significantly related to the more lung involvement in case of COVID-19 suspected pneumonia patients. These biomarkers will be helpful as diagnostic and prognostic markers for this disease. HRCT percentage can play an important role as diagnostic and prognostic tool in case of COVID-19 suspected cases.

The Spectrum of Focal Segmental Glomerulosclerosis from Eastern India: Is It Different?

Focal segmental glomerulosclerosis (FSGS) is a disease that is defined entirely by its histopathological appearance. The recent Columbian classification has grouped this disease into various types based on the light microscopic description. There is a paucity of data describing the distribution of its various subtypes from the Indian subcontinent. This study was undertaken with the aim to throw light on the epidemiology and clinical features of primary FSGS in Eastern India. This retrospective study includes our cohort of biopsy-proven FSGS who presented to us from June 2009 to July 2011 and the analysis of their presenting clinical and histopathological features from our center in East India. Out of 347 patients diagnosed with FSGS in this period, 224 patients were included in the study. A total of 167 cases were of not otherwise specified (NOS) variant (74.5%), 30 tip variant (13.39%), 14 perihilar (6.25%), 8 cellular (3.57%), and 5 to the collapsing variant (2.23%). The maximum proteinuria at presentation was seen with the tip variant (7.98 ± 6.6 g/24 h), and the renal functions were most deranged at presentation with the collapsing variant. These findings were different from those described in other populations including higher prevalence of the tip and the perihilar variant, significant difference in the degree of hypertension, proteinuria, and renal dysfunction among the different variants. The Columbian classification has helped to stratify the outcomes of this glomerular disease with respect to its clinical presentation as well as histopathological features. However, the characteristics of the various variants do show a distinctive pattern in various populations based on ethnicities.

Surgical Management of Breast Cancer under Local Anaesthesia: A Surgeon's Perspective

Background: Treatment of breast cancer without surgery may not be effective. But in elderly patients with lots of co-morbidities, surgical management often cannot be done due to the significant risks of general anesthesia. The need for a safe, easy and effective alternative anaesthetic technique that can provide adequate peroperative analgesia as well as reduced anxiety in such group of patients was the main indication for this study.Materials and method: This prospective study was done on eleven patients, with coexisting medical conditions and who were not at all fit for general anaesthesia, and underwent breast cancer surgery under local anaesthesia. The patients were studied with regard to intraoperative analgesia, haemodynamic stability and complications related to technique. The study was done in Delta Medical College Hospital, Dhaka, Bangladesh.Results: Mean±SD of study patients were 64.7±7 years old and all were suffering from coexisting medical conditions. Following local anaesthesia, mean intraoperative heart rate was 81.5±11.8 beats/min and the mean blood pressure was 127.3/79±9.6/7.0 mmHg. Patients felt no pain after infiltration of local anaesthetics, but experienced it if any place was missed before dissection. No complication occurred due to this procedure. All the candidates were fully satisfied with the procedure.Conclusion: Local anaesthesia provides satisfactory pain control along with keeping haemodynamics stable for surgical treatment of breast cancer among elderly patients having co-morbid conditions.Delta Med Col J. Jul 2017 5(2): 63-67

The Epidemiology, Clinical Features, and Outcome of Infection-related Glomerulonephritis from East India: A Single Center Experience

Infection-related glomerulonephritis (IRGN) is an example of immunological renal injury due to non-renal infections. With the changing face of IRGN over the years, renal biopsy definitely has an important role to play in differentiating this disease from the other masquerades and helps in prognosticating the long-term outcomes. This prospective study includes biopsy-proven IRGN cases who presented to us from July 2010 to July 2013 from a single center in East India. Of the 168 patients suspected and screened, 137 patients were proved to have IRGN. About 11.67% cases were proven to be immunoglobulin A-IRGN variant. The mean age of presentation was 22.7 ± 15.8 years with a slight male preponderance. A nephrotic range of proteinuria was seen in 13.8% cases and 17.5% patient required renal replacement therapy at presentation. Around 8.75% patients had persistent proteinuria despite normal renal function beyond 6 months of follow-up and 8.09% patients progressed to chronic kidney disease. It may no longer be classified as a glomerular disease with the definite favorable outcome as an important number of patients may progress to chronicity following this disease. Renal biopsy plays an important role in the assessment of prognosis of IRGN and detection of the presence of other underlying glomerulonephritis and should be considered early, especially in patients with atypical presentation.

Mitochondrial stress-induced p53 attenuates HIF-1α activity by physical association and enhanced ubiquitination

Retrograde signaling is a mechanism by which mitochondrial dysfunction is communicated to the nucleus for inducing a metabolic shift essential for cell survival. Previously we showed that partial mtDNA depletion in different cell types induced mitochondrial retrograde signaling pathway (MtRS) involving Ca⁺² sensitive Calcineurin (Cn) activation as an immediate upstream event of stress response. In multiple cell types, this stress signaling was shown to induce tumorigenic phenotypes in immortalized cells. In this study we show that MtRS also induces p53 expression which was abrogated by Ca²⁺ chelators and shRNA mediated knock down of CnAβ mRNA. Mitochondrial dysfunction induced by mitochondrial ionophore, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and other respiratory inhibitors, which perturb the transmembrane potential, were equally efficient in inducing the expression of p53 and downregulation of MDM2. Stress-induced p53 physically interacted with HIF-1α and attenuated the latter’s binding to promoter DNA motifs. Additionally, p53 promoted ubiquitination and degradation of HIF-1α in partial mtDNA depleted cells. The mtDNA depleted cells, with inhibited HIF-1α, showed upregulation of glycolytic pathway genes, glucose transporter 1–4 (Glut1–4), phosphoglycerate kinase 1 (PGK1) and Glucokinase (GSK) but not of prolyl hydroxylase (PHD) isoforms. For the first time we show that p53 is induced as part of MtRS and it renders HIF-1α inactive by physical interaction. In this respect our results show that MtRS induces tumor growth independent of HIF-1α pathway.

Consequence of neo-adjuvant chemotherapy on morphology of breast carcinoma: A systematic evaluation

BACKGROUND

Neo-adjuvant chemotherapy (NAC) in locally advanced breast cancer is the present trend. Following NAC, a considerable alteration of morphology occurs in the tumor.

AIMS

To study effects of NAC on morphology of breast carcinoma and to evaluate the pathologic response (PR).

MATERIALS AND METHODS

A total of 39 surgically resected mastectomy specimens of patients of invasive locally advanced breast carcinoma who received NAC were evaluated for macroscopic and microscopic (by routine stains and immunohistochemistry) alteration of morphology.

RESULTS

Macroscopically well-defined tumor noted in 25 cases (64.1%) and in the rest (14 cases, 35.9%), only fibrotic areas identified. Microscopic examination identified malignant cells in 29 (74.4%), significant chronic inflammation in 24 (61.5%), hyalinized fibrosed stroma in 25 (64.1%) and necrosis in 11 (28.2%) cases. Immunohistochemistry assisted in differentiating malignant cells from histiocytes. In 15 cases (38.5%), axillary lymph nodes isolated where fibrosis seen in 12 (30.8%) and malignant cell in 8 (20.5%) cases. In 34 cases where the pre-treatment biopsy were available, complete pathologic response (pCR) and partial pathologic response (pPR) were achieved in 7 (20.6%) and 23 (67.4%) cases respectively.

DISCUSSION

Protocol of systematic evaluation of morphological changes is different in cases of a patient treated by NAC. Nature of malignancy was difficult to categorize as morphology of typical breast carcinomas were altered. Sometimes, immunohistochemistry is advantageous as routine H and E stains are not sufficient to isolate malignant cells in fibrotic and necrotic areas. Appropriate morphological evaluation of the mastectomy specimen is absolutely crucial for assessment of PR and subsequent management.

Finite Element Analysis of a TMJ Implant

To determine the causes of failure of an artificial temporomandibular joint implant, one must study the magnitude and location of the maximum stresses under physiological loading. In this study, we analyzed the stresses in a commercially available TMJ implant, the bone ( i.e., mandible), and the bone-implant interface using a finite element software package. Both titanium and Co-Cr-Mo/Vitallium metals as well as bones with various degrees of osteoporosis were studied. The results of the analysis showed that the maximum stresses occurred at the location of the first screw hole (closest to the condyle) of the implant. In addition, the highest microstrains were observed in the bone adjacent to the first screw hole. The results of our study have potential clinical benefit in terms of improved implant design and hence better performance.

Nonparaxial effects on the propagation and scattering of a polarized optical pulse

Propagation characteristics of a polarized optical solitary pulse are analyzed by taking into account the effect of nonparaxiality and mutual interaction. To start with, a pair of generalized nonlinear Schrodinger equations is deduced through an operator approach. Stationary solutions of such a system are then analyzed numerically through a boundary value problem in two stages, with and without the nonparaxial effect. In the second stage, the propagating form of the corresponding spatial soliton is studied by an extended split step algorithm ETDRK. The initial profile is considered to be both a one- and two-soliton solution, to visualize the event of scattering and fusion. From this data, we have computed the intensity, root mean square spectral width, and chirp of a single soliton as it propagates. In the case of the two-soliton solution, we observe that for source parameter values, the fusion is more favored than scattering. It is observed that nonparaxiality and the interaction between A(x) and A(y) tends to destroy the periodic behaviors of these parameters. Lastly, we have investigated the modulational instability of the system as function of frequency detuning and nonparaxiality. The form of the gain is discussed as a function of nonparaxiality.

Inorganic lead exposure in battery and paint factory: effect on human sperm structure and functional activity

Lead is one of the industrially important heavy metals that causes male reproductive impairment among battery and paint factory workers, but information on the structure-function integrity of human spermatozoa is still limited. Therefore, it was necessary to investigate the effect of lead on sperm structure and functional activity in these workers. Oligozoospermia with concomitant lowering of sperm protein and nucleic acid content and the percentage of sperm DNA hyploidy (P <0.001) suggested the diminution of sperm cell production after occupational lead exposure. Low sperm vitality and hypoosmotic swelling percentage along with high malondialdehyde content and altered seminal plasma ascorbate level (P<0.001) indicating damage of sperm cell surface, might be due to high membrane lipid peroxidation and failure of non-enzymatic antioxidant protection after lead exposure. Alteration of sperm membrane surface was also evidenced from scanning electron microscopy and further authenticated by atomic and lateral force microscopy. Lowering of sperm velocity, gross and forward progressive motility with high stationary motile spermatozoa (P<0.001) suggested retarded sperm activity among the exposed workers, which was supported by high seminal plasma fructose level and reduced activity of sperm ATPase (P < 0.001). Increased incidence of teratozoospermia was also associated with high blood and semen lead level (PbB, PbS) (P<0.001). Therefore, the results suggested that lead not only affects the sperm count, but also damages the sperm structure and membrane integrity, motility and functional activity among the battery and paint factory workers.

Comment on "Nonrelativistic electromagnetic surface waves: dispersion properties in a magnetized dusty electron-positron plasma"

The theory of electromagnetic surface modes propagating along the planar interface between dusty electron-positron plasma and vacuum is reexamined by the conventional matching method of boundary conditions. It is shown that in a magnetoplasma the direct use of specular reflection method is not appropriate and the derivations for the TM-mode dispersion relation [Phys. Rev. E 61, 4357 (2000)] are incorrect.

Optically injected laser system: characterization of chaos, bifurcation, and control

A single mode semiconductor laser subjected to optical injection, described by a set of three coupled nonlinear ordinary differential equations, exhibiting chaos is considered. By means of a recurrence analysis, quantification of the strange attractor is made. Analytical studies of the system using asymptotic averaging technique, derive certain conditions describing the prediction of 1-->2 bifurcation, which have subsequently been verified on numerical simulation. Furthermore, the locus of points on the parameter phase space representing Hopf bifurcation has been derived. The problem of control of chaos by a new procedure based on adaptive stabilization is also addressed. The results of such control are shown explicitly. Though this analysis deals with a very specific set of equations, the overall features that come out of the study remains valid for almost all laser systems.

Luteolin, an abundant dietary component is a potent anti-leishmanial agent that acts by inducing topoisomerase II-mediated kinetoplast DNA cleavage leading to apoptosis

BACKGROUND

Plant-derived flavonoids, which occur abundantly in our daily dietary intake, possess antitumor, antibacterial, and free radical scavenging properties. They form active constituents of a number of herbal and traditional medicines. Several flavonoids have been shown to exert their action by interacting with DNA topoisomerases and promoting site-specific DNA cleavage. Therefore, flavonoids are potential candidates in drug design. We report here that, although the flavonoids luteolin and quercetin are potent antileishmanial agents, luteolin has great promise for acting as a lead compound in the chemotherapy of leishmaniasis, a major concern in developing countries.

MATERIALS AND METHODS

Kinetoplast DNA (kDNA) minicircle cleavage in drug-treated parasites was measured by electrophoresis of the total cellular DNA, followed by Southern hybridization using 32P labeled kDNA as a probe. Cell cycle progression and apoptosis were measured by flow cytometry using propidium iodide and fluorescein isothiocyanate (FITC)-labeled Annexin V.

RESULTS

Luteolin and quercetin inhibited the growth of Leishmania donovani promastigotes and amastigotes in vitro, inhibited DNA synthesis in promastigotes, and promoted topoisomerase-II-mediated linearization of kDNA minicircles. The IC50 values of luteolin and quercetin were 12.5 microM and 45.5 microM, respectively. These compounds arrest cell cycle progression in L. donovani promastigotes, leading to apoptosis. Luteolin has no effect on normal human T-cell blasts. Both luteolin and quercetin reduced splenic parasite burden in animal models.

CONCLUSION

Luteolin and quercetin are effective antileishmanial agents. Quercetin has nonspecific effects on normal human T cells, but luteolin appears nontoxic. So, luteolin can be a strong candidate for antileishmanial drug design.

Metallic ion concentration during menstrual cycle in normally menstruating women

Plasma concentration of metallic ions levels during menstrual cycle of twenty normally menstruating women were observed in four phases i.e. menses, follicular, ovulatory and luteal. The concentration of magnesium, zinc, selenium and manganese was highest during menses and lowest at ovulatory phase. There was rise in ionic levels of magnesium and selenium, while fall in zinc and manganese during luteal phase. Findings demonstrate changes in metallic ions (Magnesium, zinc, selenium and manganese) level in relation to hormonal status during menstrual cycle in women.

Multiple calvarial cavernous haemangiomas: case report and review of the literature

Multiple cavernous haemangiomas of the skull with erosion of the inner table and symptomatic intracranial extension were observed in a middle-aged woman. Plain radiographic and CT features are described. The literature relevant to these unusual features is briefly discussed.

Spermatogenic and steroidogenic impairment after chromium treatment in rats

Feeding of hexavalent chromium at doses of 20, 40 and 60 mg/kg daily for 90 days caused cellular impairment in rat testis. Spermatogenic inhibition coupled with deminution in testicular protein, DNA and RNA was significant at the doses 40 and 60 mg kg chromium. Decline of Leydig cell population and nuclear diameter indicated the steroidogenic impairment and the effect was confirmed by the significant inhibition of 3 beta-delta 5-hydroxy steroid dehydrogenase along with low level of serum testosterone.

Steroidogenic impairment after lindane treatment in male rats

The effect on testicular steroidogenesis after lindane (delta-isomer of hexachlorocyclohexane) administration of 4 and 8 mg/kg, i.p. daily for 45 days to male mature rats was investigated. A significant decline in testicular weight of both test groups was observed. Cellular degeneration in Leydig cells of the 8 mg/kg treated group was conspicuous. A sharp decline in the Leydig cell's population and morphological deformation were supported by the decreased activities of testicular hyaluronidase and 3 beta delta 5-hydroxysteroid dehydrogenase. A high level of testicular cholesterol and depletion of ascorbic acid were also responsible for steroidogenic impairment in the treated groups. These impairments also led to a significant diminution in serum testosterone.

Testicular toxicity of methylmercury: analysis of cellular distribution pattern at different stages of the seminiferous epithelium

Stage-specific distribution of methylmercury (MM) and spermatogenic changes were analyzed in rats administered 5 or 10 micrograms MM/kg, ip, daily for 15, 30, 60, and 90 days. MM deposition, as grain number/cm2 was noted in basal portions at later stages on day 15, which increased gradually by day 90. MM deposition was in the order of stages IV, VII, XIV, IX, being higher in adluminal portions on days 30 and 60. MM-enriched cytoplasmic masses leaked out through disintegrated tubular membrane on days 60 and 90. Epithelial damage, at stages late XIV through IV, V through VI, VII through VIII, XIII through mid-XIV, and IX through XII, accorded with the gradual deposition of MM. As profound cell death occurred between zygotenes to pachytenes and dividing spermatocytes to step 1 spermatids, the spermatids were conspicuously decreased at later times. It is possible that MM distorts the barrier system at stages IX through XII, gets distributed within the tubule, and hence may pose a direct or Sertoli cell mediated effect at stages XII through early XIV in a dose-duration-MM burden related manner.

Steroidogenic inhibition in testicular tissue of formaldehyde exposed rats

Three groups of rats (n = 10) were subjected to intraperitoneal treatment of formaldehyde daily at doses of 5, 10 and 15 mg/kg body weight over a period of 30 days. Gradual diminution in body and testicular weight was observed in all treated groups. Leyding cell impairement was conspicuous in those given doses of 10 and 15 mg/kg. Inhibition of 3 beta-delta 5-hydroxy steroid dehydrogenase and accumulation of sudanophillic materials in testicular tissue of formaldehyde treated rats was recorded histochemically. Significant decline of serum testosterone was also observed in the same groups. Structural and functional impairement of Leydig cells after formaldehyde treatment caused steroidogenic inhibition.

Distribution of mercury and evaluation of testicular steroidogenesis in mercuric chloride and methylmercury administered rats

Intraperitoneal administration of methylmercury chloride (MMC) and mercuric chloride (MC) to male rats in doses of 5, 10 micrograms MMC/kg or 50, 100 micrograms MC/kg for 90 days induced cellular disintegration of Leydig cells which was conspicuous on day 30 and onwards in the exposed groups. Progressive degeneration of Leydig cells and decrease in their nuclear diameter and population were associated with gradual increase in deposition of mercury. Gradual diminution of 3 beta-hydroxy-delta 5-steroid dehydrogenase activity in Leydig cells after MMC or MC treatment was correlated with different structural deformations of the cells over 90 days. Moreover, a significant decrease in serum testosterone levels by day 90 confirmed steroidogenic impairment after MMC or MC treatment.

BHC induced testicular impairments in rats

Benzene hexachloride (BHC) was fed to mature male rats weighing 160 g at dosages of 3 and 6 mg/kg body weight over a period of 180 days. Significant decrease in testicular weight and degeneration of seminiferous tubules with deformed spermatogenic cells were noted at a dose of 6 mg/kg BHC. Marked increase in BHC residue in testis revealed that the drug was able to cross blood-testis barrier.

Methylmercury induced biochemical and histochemical alterations in rat testis

The methylmercurry chloride (MMC) administered at doses of 5 and 10 micrograms/kg over a period of 90 days to male rats caused enzymatic impairments in testicular tissue. The study at intervals of 15, 30, 60 and 90 days showed gradual diminution of testicular weight and gradual decrements in testicular protein and inhibition in testicular succinic dehydrogenase activity. Histochemical and biochemical studies revealed that testicular acid phosphatase activity was also inhibited at both the doses of MMC treatment. The inhibition of enzyme activity in testicular tissues after MMC treatment caused the impairment of both spermatogenesis and steroidogenesis in rats.

Methylmercury- and mercuric-chloride-induced alterations in rat epididymal sperm

Four-week-old male albino rats weighing 70 +/- 5 g were treated intraperitoneally daily with 0, 5 and 10 micrograms methylmercuric chloride (MMC)/kg or 0, 50 and 100 micrograms mercuric chloride (MC)/kg body weight, respectively, over a period of 90 days. Studies were carried out a intermittent intervals, i.e. on days 0, 15, 30, 60 and 90 of the experiment. Gradual decrements in body and epididymal weights were observed from day 30 onwards in both the MMC- and MC-treated groups. Morphological deformations of epididymal epithelium were noted from day 30 onwards in the mercurial-treated groups. MMC treatment caused severe degeneration of the epididymal epithelium on days 60 and 90 in comparison to MC treatment. Total sperm count was significantly less in the MC-treated groups, while motile sperm count was affected most in the MMC-administered groups. The frequency of sperm abnormality increased consistently at both doses of mercurial treatment over a period of 90 days. Maximum sperm abnormality among the treated groups was noted in the groups given 10 micrograms MMC/kg. The observations revealed that MMC and MC have variable potency to alter epididymal structure and the sperm.

Histological and pharmacological changes in vas deferens of rats exposed to hexachlorocyclohexane

The effect of hexachlorocyclohexane (HCH) treatment in male albino rats at dosages of 3 and 6 mg/kg body weight by force-feeding were studied over a period of 180 days. Histological observations revealed graded degeneration in the muscular layer of vas deferens. Moreover, the accumulation of HCH residue in serum and vas deferens is highly significant in the experimental group. The contractility of muscles showed marked inhibition by in vitro study.

Trace elements in the endometrium of infertile women

Some essential trace elements were estimated in endometrium of regularly menstruating fertile women and in women with infertility due to cervical factors. The distribution of the trace elements zinc, copper, iron, selenium and manganese at any particular phase of cycle remains more or less semilier between control (i.e. fertile) and infertile (primary and secondary) subjects.

The infant mortality-fertility debate: some international evidence

"The aim of this paper is to analyze empirically the causal relationship, if any, between infant mortality and fertility in thirty-five developing countries." The focus is on possible relationships between the infant mortality rate and the fertility rate. "The hypothesis that infant mortality causes fertility is tested. The possibility of a 'reverse causation' is also analyzed. A one-sided distributed lag test as proposed by Granger...is employed." The results are analyzed in light of several versions of the mortality-fertility proposition, including demographic transition theory, choice theory, Ricardian theory, and the modern economic theory of population.

Effect of lead on erythropoietic system of intact and splenectomized rats

Erythropoietic alterations in normal and splenectomized mature male rats treated with aqueous lead acetate intraperitoneally at dosages of 4 mg/kg and 6 mg/kg body weight were observed over a period of 30 days. Significant retardation in growth might be due to gradual increases in lead toxicity. The elevated blood lead level, increased urinary delta-amino-levulinic acid (ALA-U) excretion, depletion in RBC and haemoglobin content and more number of reticulocytes in peripheral blood indicated the increased intensity of lead toxicity and inhibitory effect on haem biosynthesis. The accelerating action of lead on erythropoietic cellular series i.e. pronormoblast, early and intermediate normoblast and late normoblast was evident by the significant increase in number of cellular count both in intact and splenectomized rats after treatment with lead.

Testicular regulation and sub-cellular distribution of zinc in the epididymis and vas deferens of rhesus monkey (Macaca mulatta)

The zinc concentration in the epididymis (caput, corpus and cauda regions), vas deferens and caudal lobe of prostate of adult rhesus monkeys was determined by atomic absorption spectrophotometry. Zinc content (microgram/g wet weight) was found to be maximum in the prostate (709 micrograms) followed by epididymis and vas deferens. The three segments of the epididymis did not differ from one another in their zinc content (165-177 micrograms). On a protein basis maximum concentration of zinc was present in the nuclear fraction followed by microsomal, cytosolic and mitochondrial fractions in that order. Ligation of testicular efferent ducts or castration 90 days prior to autopsy caused a marked reduction in zinc concentration in different sub-cellular fractions of the organs examined; castration was relatively more effective in this regard. The importance of androgen and other testicular products in controlling zinc content and the possible physiological role of zinc in the male genital tract are discussed.

Effect of lead on human semen

Semen qualities were studied in workers with an average age of 30 years and occupationally exposed to lead in a printing press. Another sample with the same average age but not exposed to lead were taken as control subjects. The average lead content in blood and seminal plasma of the exposed group were 42.5 mcg/100 ml and 14.80 mcg/100 ml, respectively. Their sperm counts and percentage of motile sperm were significantly affected. Significantly higher percentages of abnormal spermatozoa were also observed in these semen samples. The levels of seminal acid phosphatase, succinic dehydrogenase, and fructose in them were also significantly found to be low compared with those from the unexposed subjects. Cytochemical study of sperm head DNA in the exposed groups showed a low surface reaction.