Histological and histometrical studies of testicular hypertrophy following hemicastration of albino rats

This project was designed to study the effects of hemicastration in male albino rats of different ages and weights. Significant compensatory hypertrophy was seen in young rats (5 and 20 days old). The concentration of seminiferous tubules was profoundly reduced while the tubular diameter was increased in young hemicastrated rats. The weights of the kidneys were increased while the weights of the adrenal glands were not different in hemicastrated young rats. These histological and histometrical changes may be associated with specific endocrine activity.

Application of electron microscopy in the interpretation of fine-needle aspiration biopsies

A series of 31 fine-needle aspiration biopsies were studied ultrastructurally in order to evaluate the usefulness of electron microscopy in the diagnosis of aspiration biopsies. In seven cases, the electron microscopic findings were crucial to the diagnosis. In the remaining cases, electron microscopy helped to confirm the light microscopic diagnosis. In addition, in a number of cases the diagnosis rendered following electron microscopy was much more precise and specific than was possible with light microscopy alone. It is concluded that electron microscopy has a definite place in the diagnosis of fine-needle aspiration biopsies and should be increasingly utilized on a selective basis.

Ultrastructure of the pineal organ of the killifish, Fundulus heteroclitus, with special reference to the secretory function

The pineal organ of the killifish, Fundulus heteroclitus, was investigated by electron microscopy under experimental conditions; its general and characteristic features are discussed with respect to the photosensory and secretory function. The strongly convoluted pineal epithelium is usually composed of photoreceptor, ganglion and supporting cells. In addition to the well-differentiated photosensory apparatus, the photoreceptor cell contains presumably immature dense-cored vesicles (140-220 nm in diameter) associated with a well-developed granular endoplasmic reticulum in the perinuclear region and the basal process. These dense-cored vesicles appear rather prominent in fish subjected to darkness. The ganglion cell shows the typical features of a nerve cell; granular endoplasmic reticulum, polysomes, mitochondria and Golgi apparatus are scattered in the electron-lucent cytoplasm around the spherical or oval nucleus. The dendrites of these cells divide into smaller branches and form many sensory synapses with the photoreceptor basal processes. Lipid droplets appear exclusively in the supporting cell, which also contains well-developed granular endoplasmic reticulum and Golgi apparatus. Cytoplasmic protrusions filled with compact dense-cored vesicles (90-220 nm in diameter) are found in dark-adapted fish. The origin of these cytoplasmic protrusions, however, remains unresolved. Thus, the pineal organ of the killifish contains two types of dense-cored vesicles which appear predominantly in darkness. The ultrastructural results suggest that the pineal organ of fish functions not only as a photoreceptor but also as a secretory organ.

[Retinal adaptations to habitat]

Vertebrates have, through the process of evolution, adapted to their photic environment. This is well manifested in the retinal adaptations to various habitats. Although all vertebrates are considered, emphasis is placed on fishes because they form about 50% of the vertebrate species. In addition, they occupy a wide range of habitats, thus retinal modifications of fishes serve as models for all other vertebrates. The present article reviews morphological, physiological and biochemical retinal adaptations. The quality and quantity of light reaching the aquatic organism are functions of the incident light as well as the aquatic environment. Thus, in well lit, clear waters fishes are arhythmic and possess almost equal populations of rods and cones; whereas fishes in dimly lit environments (due to turbidity or depth) have retinas that are more specialised for high sensitivity-multi-banked retinas, long outer segments, grouped photoreceptors, hypertrophied ellipsoid mitochondria, reflecting tapetum. Similarly, the ratio and distribution of visual pigments (rhodopsin and porphyropsin) and S-potential change with respect to fresh/sea water, clear/turbid water and air/aquatic environments. Thus, in fresh waters, where the photic environment shifts to longer wavelengths, porphyropsin predominates; while in land vertebrates and almost all marine fishes the dominant pigment is rhodopsin. With respect to the latter, fishes in turbid, greenish or yellowish coastal waters have 'rhodopsins' with lambda mas above 500 nm; fishes in clear coastal habitats have 'rhodopsins' with lambda max near 500 nm; while those in the blue-lit environment of deep seas have lambda max below 500 nm. The retinal pigment composition is also associated with habitat changes during diadromous migrations in fishes or during amphibian metamorphosis. It is interesting to note that the dorsal and ventral retinas of Rana catesbeiana and Anableps microlepis which view aquatic and aerial environments, respectively, show a predominately porphyropsin-rich dorsal retina compared to a rhodopsin-rich ventral retina. Similar shifts in the S-potential are observed with change in habitats. Fresh water fishes exhibit L-responses with lambda max in longer wavelengths compared to marine fishes where the maximum of the L-response shifted towards shorter wavelengths.

Microtubules and 10 nm-filaments in the retinal pigment epithelium during the diurnal light-dark-cycle

Microtubules and 10 nm-filaments appear to be involved in the functions of the retinal pigment epithelium (RPE). The presence of microtubules in the RPE of light-adapted eyes, but not in dark-adapted eyes, suggests that they may be involved primarily in organelle movement. On the other hand, the random and constant presence of 10 nm-filaments within the basal portion of the PE implies a cytoskeletal role for these filaments.

Sickle cell traits in Canada. Trimodal distribution of Hb S as a result of interaction with alpha-thalassaemia gene

A trimodal distribution of the amounts of Hb S in 56 sickle cell heterozygotes was observed. The variable amounts of Hb S were directly related to the mean cell volume and the mean cell Hb and were a result of the difference in net synthesis of Hb S due to the presence of the alpha-thalassaemia. Double heterozygotes for the Hb S and alpha-thalassaemia-1 genes, besides having a lower amount of Hb S in the red blood cells, were found to have lower Hb and slightly elevated Hb A2 levels.

A simple method for processing fine-needle aspiration biopsy specimens for electron microscopy

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Primary hepatocelluar carcinoma in Saudi Arabia. A clinicopathological study of 54 cases

A high incidence of primary hepatocelluar carcinoma in the Orient and Africa has been reported. It is also seen frequently in Saudi Arabia. In a series of 54 consecutive patients diagnosed histologically, the male to female ratio was 10:1--the highest reported. The peak age was between 40-60 years and the mean survival was eight months. This is in contrast to hepatocelluar carcinoma in Africa where the age is between 25-35 years and the disease runs a quick downhill course simulating an abscess. Macronodular cirrhosis was diagnosed histologically or suggested clinically in 80% of the cases. Serum was positive for HBsAg in 55% of the patients, compared with 8% in healthy blood donors. These figures are as significant as reports from high incidence areas and point strongly to a possible causal relationship between HBV infection and the development of primary hepatocellular carcinoma.

Cone myoid elongation and rod myoid contraction are inhibited by colchicine in the trout retina

Retinal photoreceptors of lower vertebrates undergo photomechanical changes (elongation or shortening) in response to light or dark. Colchicine, a microtubule-disrupting drug, blocks cone, but not rod elongation. Instead, rod shortening is blocked by this drug, thus suggesting that different mechanisms mediating these responses are involved in rods and cones.

Lepromatous leprosy presenting as orchitis

Two patients with lepromatous leprosy presenting initially because of lepromatous orchitis are reported. These cases are unusual because they were diagnosed as lepromatous orchitis at a stage when no other evidence of leprosy was present. Generalized skin lesions characteristic of lepromatous leprosy subsequently developed in one of these patients. It is suggested that lepromatous orchitis should be actively considered in the differential diagnosis of orchitis and infertility.

Responses of pineal photoreceptors in the brook and rainbow trout

Electron microscopy of the pineal receptor cells in light- and dark-adapted brook trout, Salvelinus fontinalis and the rainbow trout, Salmo gairdneri, revealed no significant differences in the tubular and filamentous elements of the inner segment, neck and supranuclear regions. However, changes in synaptic relations between the photoreceptor and nerve cell were induced by light and darkness. In the light-adapted state, the synaptic relationship between axon terminals and photoreceptor basal processes predominates, while in darkness the synapses between photoreceptor basal processes and ganglion cell dendrites are more prominent. Further, in darkness, the photoreceptor basal processes show a number of synaptic vesicles and synaptic ribbons. These findings suggest that the sensory function of the fish pineal is enhanced during darkness but inhibited by light, and that the synaptic relationships are involved in the control of sensory activity in the pineal photoreceptor and ganglion cells. These results corroborate those of electrophysiological studies in that the maximal spontaneous discharge frequency of the ganglion cells occurs in the dark, and it also shows a burst when light is removed. The "typical" chemical synapse between the axon terminal and the photoreceptor basal process in light seems to function as an inhibitor.

Oral therapy in children with cholera: a comparison of sucrose and glucose electrolyte solutions

We performed a double-blind trial comparing sucrose electrolyte oral solution with glucose electrolyte oral solution in children less than 5 years of age with severe cholera-like diarrhea. Of 111 patients studied (102 with bacteriologically confirmed cholera), 55 received sucrose solution and 56 received glucose solution. The success rates, as defined by the absence of the need to give unscheduled intravenous therapy, were similar in the two groups (73% and 77% in the sucrose and glucose groups, respectively). There was no difference in purging rates between the two groups. The primary determinant of success for oral fluid regardless of the sugar was the purging rate. Sucrose malabsorption was responsible for oral therapy failure in one child. This study demonstrates that sucrose is an effective alternative to glucose in the oral therapy solution, but either must be used in conjunction with intravenous solution when treating severe dehydrating diarrhea.

Haemoglobin D Los Angeles, D-beta +-thalassaemia, and D-beta o-thalassaemia. A report of two Canadian families

The first 2 Canadian cases of combinations of Hb D Los Angeles and beta-thalassaemia were found in an Italian family and an East Indian family in Hamilton, Ont. The structure of the Hb D variant was identified by radioimmunoassay. The beta +-thalassaemia trait in the Italian family and the beta o-thalassaemia trait in the East Indian family were confirmed by studies of globin chain synthesis. Previous cases of Hb D-beta-thalassaemia were summarized and family studies of the 2 new cases were presented.

A new case of the unstable haemoglobin Genova (alpha 2 beta 2 28 (beta 10) leu leads to pro) in Canada: as a result of sporadic mutation and causing Heinz body haemolytic anaemia

The first case of the unstable Hb Genova as a result of sporadic mutation is described. It is found in a 3-year-old Canadian boy of East Indian extraction with chronic Heinz body haemolytic anaemia.

Laboratory diagnosis of HB CC-alpha-thalassemia

Routine laboratory investigations of hemoglobinopathies include Hb electrophoresis for abnormal hemoglobins, determination of Hb A2 (alpha 2 delta 2) for beta-thalassemia traits, staining for Hb H (beta 4) inclusions for alpha-thalassemia traits and estimation of Hb F (alpha 2 lambda 2) for the presence of hereditary persistence of fetal hemoglobin genes (HPFH). Frequently, analytical column chromatography and alpha/beta hemoglobin chain synthesis are used in the studies of more complicated hemoglobinopathies. This communication outlines the procedures used in this laboratory for the diagnosis of a case of Hb CC-alpha-thalassemia.

The effects of hypophysectomy on the retinomotor responses of the killifish, Fundulus heteroclitus

This paper presents the results of an investigation concerned with the effects of long-term hypophysectomy on the retinomotor responses of the euryhaline killifish, Fundulus heteroclitus: 1. The eye of hypophysectomised Fundulus heteroclitus responds to light and dark in the same manner as that of intact controls: the retina is not in a state of permanent light-adaptation as claimed by Vilter (1942) for the hypophysectomised eel. 2. There is no evidence of a persistent circadian rhythm during continous darkness. 3. Unilateral illumination of the eye of intact fish results in dispersion of retinal pigment in both illuminated and unilluminated eyes, as in the goldfish (Ali, 1964), but no such contralateral response was evident after hypophysectomy. The cones are unresponsive.

Myotube formation in skeletal muscle regeneration

Muscle fibre regeneration in the latissimus dorsi of adult rats has been studied by light and electron microscopy. Both 'continuous' and 'discontinuous' modes of regeneration occur. In 'continuous' regeneration sarcoplasmic buds grow from the damaged muscle fibres, their nuclei apparently originating from the healthy portion of the muscle fibre. In 'discontinuous' regeneration mononucleated cells accumulate inside intact but vacated, sarcolemmal tubes. They differentiate into myofibril-containing myoblasts which later fuse. 'Continuous' regeneration occurs when the sarcolemmal sheaths are disrupted; 'discontinuous' regeneration when the sarcolemmal sheaths remain intact.

The Crystal Structure of [2,6-Bis(1-methyl-4-methylthio-5-thia-2,3-diazahexa-1,3-dienyl)-pyridine]dithiocyanatonickel(II), a Complex of a Potentially Pentadentate N3S2 Ligand, and a Comparison with Complexes of an N3O2 Ligand

The crystal structure of Ni(dapsm)(NCS)2 [dapsm is 2,6-bis(1-methyl-4-methylthio-5-thia-2,3-diazahexa-1,3-dienyl)pyridinel has been determined from three-dimensional single-crystal diffractometer X-ray data. Structure refinement was carried out by least-squares methods to a final R value of 0.059. The ligand dapsm is a potential N3S2 pentadentate, but it coordinates as a tetradentate, giving a planar N3S donor grouping. Rotation occurs about an N-N bond in dapsm, moving a potential donor sulfur atom away from the nickel(II) ion. The pyridine ring of the ligand, and the N3S donor grouping, are approximately coplanar. Two thiocyanate groups are coordinated to the nickel, giving a distorted octahedral structure. The structure and electronic spectrum of Ni(dapsm)- (NCS)2 are compared with those for seven-coordinate complexes with the related N3O2 ligand, 2,6-diacetylpyridine bissemicarbazone.

Microspectrophotometric studies on the visual pigment in the intact retina of the goldfish, Carassius auratus (Linn.)

The visual pigments in intact retinas of the common goldfish were examined by microspectrophotometry. Difference spectra free of photoproduct contamination had absorbance maxima at lambda527 nm +/- 2 nm. The average pigment density, about 0.32, was almost invariant with regard to retinal location and specimen size. Traces of a photoproduct absorbing maximally at lambda480-490 nm were found. The normalized "absorbance" curve deviated from standard templates. It was suggested that this was an effect of cross-coupling of energy and among photoreceptors. Finally, known action spectra show a red shift relative to the absorbance spectra measured.

Oral hydration rotavirus diarrhoea: a double blind comparison of sucrose with glucose electrolyte solution

Of 57 male children, aged 5 months to 2 1/2 years with rotavirus diarrhoea, 28 were given oral therapy with sucrose electrolyte solution and 29 were given glucose electrolyte solution in a randomised double-blind trial. All were rehydrated and remained so on oral therapy alone. These patients were compared with 44 children, also with rotavirus, who were treated only with intravenous hydration. The oral therapy and intravenous therapy groups did not differ clinically in the rate of rehydration or the rate of purging. Vomiting did not prevent the giving of oral therapy during hospital admission. Bangladeshi children with rotavirus diarrhoea have a defect of carbohydrate digestion but this defect does not prevent the use of a sugar electrolyte solution for oral hydration.

Retinal organisation in goldeye and mooneye (Teleostei: hiodontidae)

This paper presents the results of a comparative investigation of the retinas of two Hiodontids, the goldeye (Hiodon alosoides) and the Mooneye (H. tergisus) employing light and electron microscopy, cell isolation techniques as well as microspectrophotometry. Contrary to the observations of previous workers these species possess a duplex retina. The photoreceptors are bundled in groups of 20 rods and 20 cones. They exhibit features which have hitherto not been observed in vertebrates. These are a) an ellipsoid divided in two parts by the myoid: b) tubules in cone outer segments and, c) large "lateral sacs" (accessory outer segments). Cones are immobile but the rods and epithelial pigment are capable of movement (retinomotor responses). The prominent reflecting layer consists of cuboid and rod-like crystals composed of uric acid. The inner layers are made up of three tiers of large horizontal cells, one of amacrine cells and scarce bipolar and ganglion cells. Bundle density is 1 700 per sq. mm. Roughly, one receptor bundle projects onto one bipolar and one ganglion cell suggesting that each bundle acts as a functional unit. The visual pigment of the mooneye absorbs maximally at 535 +/- 2 nm, and is based on vitamin A2 (porphyropsin). We suggest that all non deep-sea fishes with bundled receptors have duplex retinas and the adaptive mechanisms for vision in turbid waters are based on different morphological means as illustrated by the comparison with Stizostedion.

[Scotopic visual pigments in 3 Percidae: Perca flavescens, Stizostedion vitreum and S. canadense]

The scotopic visual pigments of three percids from Quebec waters, viz. the yellow perch (Perca flavescens), the walleye (Stizostedion vitreum) and the sauger (S. canadense), were studied in situ using a microspectrophotometer-computer complex. The difference spectra show that the three fishes possess a porphyropsin whose lambda max. is at 530 nm in the yellow perch, 533 nm in the walleye and at 536 in the sauger. This variation corresponds to the tendency of the visual pigments to fit the preferred environments. The three species studied also have different modes of life. The yellow perch inhabits mostly shallow, clear waters while the walleye and sauger prefer turbid waters. The retinal structure and responses also differ among them. Since the difference in lambda max. is so small, the differences in habitat and behaviour may be attributed to morphological differences in the retina rather than to its visual pigment content.

Photoreceptors and visual pigments in a cichlid fish, Nannacara anomala

Correlation of visual pigment content and photoreceptor cell structure is studied in the cichlid fish Nannacara anomala the retina of which is characterized by simple organization of the outer plexiform layer. The visual cell types consist of long and bulky rods and only two types of cones: equal double cones and short single cones. Both types of cones differ form other known teleost cones in that their outer segments are very slender yet twice as long as the inner segments. The double cones form a square mosaic with four doubles along the sides an a single cone in the center. Four rods usually surround the single cone and a few others lie in the corners of the square. The population densities of photoreceptor cells in the central part of the retina is 45,600 cones and 52,600 rods per mm2. The cone to rod ratio is 1:1.15; the double cone to single cone ratio is 4.07:1. The outer segments of photoreceptors contain four spectroscopic types of pigment: one type in rods with lambda max = 498 +/- 5 nm, one type in single cones with lambda max = 460 +/- 5nm, and one in each member of the double cones with lambda max of 555 +/- 5 and 600 +/- 10 nm. Single cones are found to contain only the blue-absorbing pigment. The double cones, whenever both members are successfully recorded from, appear to use two spectrally different pigments. Based on spectral bandwidth determination, the four pigments are probably of the prophyropsin class, although some admixture (10--20%) of rhodopsin-class pigments is also indicated, especially in double cones.

Preleukaemia and reticulocytosis: a case report with in vitro evidence for abnormal reticulocyte maturation

A case of preleukaemia with marked reticulocytosis and a slightly reduced red cell 51Cr survival is presented. An in vitro 'reticulocyte survival' test suggested that the apparent reticulocytosis was due to delayed maturation of reticulocytes. The globin synthesis ratio suggested an abnormal ribonucleic acid. At autopsy, in addition to the findings of acute leukaemia, mesenteric lipodystrophy was discovered. This abnormality has been seen in patients with malignant diseases, especially lymphomas, but heretofore has not been reported in acute leukaemia.

Hemolytic anemia in patients receiving sulfasalazine

Hemolytic anemia is a well-recognized complication of sulfasalazine treatment. 17 of 40 (43%) patients with inflammatory bowel disease receiving sulfasalazine had evidence of hemolysis as detected by starch gel electrophoresis. Only 47% (8) of patients with hemolysis had Heinz body formation. The hemoglobin was significantly reduced in patients with hemolysis and 53% had a reticulocyte count of greater than 5%. A significant correlation was noted between hemolysis and serum sulfapyridine level, but no correlation was seen with serum sulfasalazine level. There was no significant difference in disease extent or activity in patients with hemolysis compared to those without hemolysis. Hemolysis is not a rare side-effect of sulfasalazine therapy. Heinz body formation is not invariably found in sulfasalazine-induced hemolysis.

Diagnosis of intravascular haemolysis using starch gel electrophoresis

Starch gel electrophoresis was used to screen for intravascular haemolysis in 15 patients with clinical disorders known to be characterized by intravascular haemolysis. Decreased serum haptoglobins, increased free plasma haemoglobin and the presence of methaemalbumin was documented in all 15 patients. It is suggested that starch gel electrophoresis and staining with haem specific stain is a simple and reliable method for confirming intravascular haemolysis.

Cone synaptic ribbons and retinomotor changes in the brook trout, Salvelinus fontinalis (Salmonidae, Teleostei), under various experimental conditions

Cone synaptic ribbons in the brook trout were studied and compared with retinomotor responses during a normal 24-h cycle and during 72 h of constant light or darkness. There is a reduction of synaptic ribbons to 65% of the daytime value during a normal night. In the absence of light stimuli, retinomotor movements cease after 20–30 h, whereas rhythmic oscillations of synaptic ribbons, although dampened, persist until the 3rd day. It appears that in the brook trout, which is an arhythmic fish, there is no endogenous control of retinomotor responses and only very little control of synaptic ribbons. The significance of synaptic ribbons for synaptic transmission and of their involvement in endogenous circadian rhythms is discussed.

Megaloblastic anemia in patients receiving total parenteral nutrition without folic acid or vitamin B12 supplementation

Pancytopenia developed in four patients receiving postoperatively total parenteral nutrition (TPN). Symptoms and signs were related mainly to underlying bowel disease. Hematologic abnormalities, first noted from 4 to 7 weeks following institution of TPN, consisted of normocytic anemia (mean decrease in hemoglobin value, 2.2 g/dL), occasional macrocytes being noted, leukopenia (range of leukocyte counts, 1.2 to 3.6 X 10(9) L), some hypersegmented neutrophils being detected, and clinically significant thrombocytopenia (range of platelet counts, 25 to 52 X 10(9)/L). In all patients the bone marrow showed megaloblastic changes, with ring sideroblasts, although pyridoxine was included in the TPN regimens. Serum vitamin B12 values were normal in one patient and at the lower limit of normal in the other two patients in whom it was measured, while serum or erythrocyte folate values, or both, were reduced in three patients. Full hematologic response was observed in the four patients after folic acid replacement therapy; leukocytosis and thrombocytosis were noted in three. Thus, folic acid and possibly vitamin B12 should be added routinely to TPN regimens to prevent deficiency of either substance.

Retinal structure in Synbranchus marmoratus with observations on two new cone myoid inclusions

The retina of a South American swamp eel, Synbranchus marmoratus (Synbranchidae), was studied by Golgi impregnation, light and electron microscopy. Its principal features include (1) the presence of a dense matrix, possibly a new type of tapetum lucidum, in the pigment epithelium, (2) a well developed photoreceptor layer containing large rods, single, double and triple cones, and (3) well developped inner nuclear and plexiform layers, with the exception of horizontal cells which are few and relatively small. These and other observations are discussed in relation to the photic environment and habits of this fish. The presence of microfilament bundles and two unusual features, microtubuleladen dense bodies and paracrystalline inclusions, in cone myoids are discussed in terms of their possible involvement in retinomotor responses.

Subacute staphylococcal meningitis secondary to postpartum endometritis

A woman with Staphylococcus aureus meningitis following postpartum endometritis presented with lumbar backache and fever of several weeks' duration. Thick, green exudate was aspirated at lumbar puncture hours before death. Histologic examination demonstrated subacute inflammation of the meninges and chronic inflammation of the endometrium. Although rare, postpartum endometritis followed by low back pain and fever should alter the physician to the possibility of serious infection involving the central nervous system. Diagnosis and treatment at this early stage would be expected to decrease mortality.

Effect of lead on globin synthesis in vitro

A defect in heme synthesis is well documented to occur in lead intoxication. Globin synthesis and the alpha/beta globin chain synthesis ratio have been shown to be disturbed in lead poisoning. To elucidate further the nature of the inhibitory effect of lead on hemoglobin synthesis, reticulocyte-rich peripheral blood samples have been incubated with lead at concentrations of 10(-6), 10(-5), and 10(-4) M, equivalent to 20, 200, and 2,000 mug/dl (.96, 9.6 and 96.0 mumol/l), respectively. The incorporation of tritiated leucine into globin was determined. Globin chain synthesis decreased to 85, 49 and 15% of the control value with increasing lead concentrations. The effect of heme on inhibition of globin synthesis by lead was studied by incubating reticulocyte-enriched blood with lead 10(-5) M (200 mug/dl; 9.6 mumol/l) in the presence or absence of heme at a concentration of 10(-3) M. Lead alone depressed the incorporation of tritiated leucine to 45% of control, while globin synthesis with heme alone was 109% of control. Although in the presence of both heme and lead, the mean incorporation of leucine into globin was 69.2% of control, the increase was not significantly different from that obtained with lead alone. It is concluded that (1) lead has an inhibitory effect on globin synthesis at a concentration considered to be within the acceptable range encountered in environmental lead pollution, and the extent of inhibition is dose-dependent; (2) the effect of lead on globin synthesis is not significantly prevented by heme and, therefore, does not appear to be mediated through the well-documented inhibitory effect of lead on heme synthesis.

Value of serum copper measurement in acute leukaemia of childhood

Serum copper level (SCL) determination was carried out on sixteen normal children and on 16 with acute leukaemia. A significant increase in SCL was observed in cases of leukaemia than in normal controls. Drop of SCL occurs in cases who respond to quadruple chemotherapy, while those who failed to respond showed persistantly high serum copper level.

Scanning electron microscopy of four teleostean retinas

The morphology of the retinas of the goldeye Hiodon alosoides (fam. Hiodontidae), the brook trout Salvelinus fontinalis (fam. Salmonidae), the yellow perch Perca flavescens and the walleye Stizostedion vitreum (fam. Percidae) was studied by SEM. Semi-thin plastic sections of the same retinas were also examined for comparison. Contrary to observation of earlier authors the goldeye retina was found to possess both rods and cones; in the case of the other three fishes' retinas, present observations correspond to previous ones, adding only details. SEM gives an impressive, three dimensil view of the gross surface features of the retinas. Shrinkage during the processing of the specimens for SEM, while not altering the general topography, does induce artifacts in both plexiform layers.

The hypochromic anemias

Hypochromic anemia is the commonest type of anemia encountered in family practice. Although iron deficiency is by far the most common cause, it cannot be readily distinguished from hypochromic anemia due to other causes (thalassemia, secondary anemia and sideroblastic anemia) without knowing the state of the tissue iron stores. Treatment with iron should not be commenced until this is known. To establish the reason for the hypochromic state, the following tests are suggested: serum ferritin, bone marrow assessment of iron stores, plus serum iron and iron binding capacity.

Hemoglobin Bethesda, beta 145 (HC2) Tyr replaced by His, in a Canadian family

A hemoglobin mutant with the mobility of hemoglobin (Hb) A on alkaline cellulose acetate or starch gel electrophoresis and mobility between Hb A and Hb S on citrate agar electrophoresis was detected in a patient with erythrocytosis. Structural analysis shows a substitution of histidine by tyrosine at position 145 in the beta-chain.

[Role of the epiphysis in the migration of retinal epithelial pigment during unilateral photic stimulation in Salmo irideus]

Unilateral exposure of dark-adapted fishes indicates that the exposed eye is only partly in a light-adapted state in so far as the position of the epithelial pigment and cones is concerned. This does not occur in epiphysectomized fishes indicating a possible role of the epiphysis. On the basis of available evidence, the nature of the epiphysis role is envisaged and a suggestion made that melatonin, whose synthesis is related to dark, may play a role in this phenomenon.

Massive colchicine overdose: a report on the toxicity

A case of an overdose of colchicine for suicidal purposes is presented. The main complications observed involved the hematopoietic, the gastrointestinal, the respiratory and the central nervous system. Heinz bodies were noticed in the red blood cells, a finding which had not been previously documented in patients with colchicine overdose. Despite intensive management the patient died on the thirteenth hospital day of central nervous system complications.