Asplenia and polysplenia syndrome

This report described the morphological characteristics of seven cases of asplenia syndrome and three of polysplenia syndrome. Each syndrome has been characterized by a tendency for symmetric development of normally asymmetric organs, with varying degrees of cardiovascular anomalies. These latter anomalies are usually present in asplenia syndrome to a greater extent than in polysplenia syndrome. While, as observed in our material, the conotruncal anomalies were present more commonly in cases with asplenia, and absence of inferior vena cava with azygos continuation was seen specifically in all the cases with polysplenia. This evidence implied the presence of some pathogenetic distinction between the two syndromes.

Correlation of urothelial morphologic characteristics with the development of bladder carcinomas in BALB/c female mice administered 2-acetylaminofluorene

Urinary bladders from 6909 of 24,172 control or 2-acetylaminofluorene (2-AAF) treated female BALB/c mice were examined histopathologically. Dietary doses of 2-AAF ranged from 75 to 150 p.p.m. for up to 33 months. Urinary bladder epithelial hyperplasia, vacuolization, and inflammation were frequent observations in treated animals and showed a positive correlation with dose level and length of administration of 2-AAF. Concretions were infrequently found and occurred only in controls. Squamous metaplasia, ulceration, and lymphocytic accumulations were infrequently noted but gave some indication of a positive correlation with 2-AAF dose level. Vacuolization was always associated with hyperplasia and/or bladder tumors. Observations on the concurrence of hyperplasia, vacuolization, and neoplasia suggest that both hyperplasia and vacuolization may be precursors of neoplasia. While inflammation was infrequently noted in non-tumor-bearing animals, greater than 90% of the time it was seen in association with tumors and appears to be a response of the bladder to tumor progression.

[Therapeutic effect of ticarcillin against severe infection in patients with hematologic malignancy (author's transl)]

Seventy patients with severe infection accompanying hematologic disorders including leukemia and lymphoma were treated with ticarcillin in combination with aminoglycosides and/or cephem derivatives. Of the 58 patients in whom the efficacy could be evaluated, 17 (29%) responded markedly and 22 (38%) moderately, the effective rate being 67%. Side effects attributable to the treatment were noted: rash in 2, fever and rash in 1, vascular pain in 2 (5 and 7 years of age). Renal and hepatic functions were abnormal in 4 each. However, these abnormal findings were not attributed to ticarcillin. These results indicate that ticarcillin is an effective and safe antibiotic for the treatment of severe infection accompanying hematologic malignancy when used in combination with aminoglycosides and/or cephem derivatives.

Internal carotid occlusion: volume of cerebral infarction, clinical findings, and prognosis

Clinical, angiographic and computed tomographic (CT) findings, and the volume of an infarcted area as estimated from tomograms, were evaluated in 26 patients with proven, unilateral, internal carotid artery (ICA) occlusion. The volume of cerebral infarction (CI) ranged from 0 cm3 to 200 cm3. It was shown that the CI volume in the group of patients with good collateral flow was smaller than that in the group with poor or no collaterals (p less than 0.05). It was also found that the smaller the volume of infarcted area, the better the patient's ability to carry out activities of daily living (ADL). The volume of infarction in patients without disturbance of consciousness was smaller than in patients with such disturbance. Thirteen of 15 patients with infarction of less than 50 cm3 eventually showed good ADL. The patients with a deeply located infarction had a good prognosis and no disturbance of consciousness. In patients with superficial infarction there were relationship between the volume of infarction and prognosis, and between the volume and disturbance of consciousness. It is concluded that estimation of the volume of an infarcted area is important in assessing the clinical state and prognosis in patients with ICA occlusion.

Diagnosis of internal carotid artery occlusion by dynamic computed tomography

To evaluate internal carotid artery occlusion noninvasively by means of computed tomography (CT), dynamic CT studies with intravenous bolus injection of contrast medium were performed in 13 patients with hemispheric cerebral infarction and one patient with vascular headache. The slice level of dynamic CT was fixed at the atlas. The initial CT scan was taken after the start of infection of 20 or 40 ml of 60% meglumine amidotrizoate (this scan was used as a precontrast density reference), and 10 additional scans were made during 51.6 sec from the start of injection. The occluded internal carotid arteries were not visualized in patients with ICA occlusion, while all nonoccluded internal carotid arteries proven by angiography were enhanced clearly. It is concluded that this simple and noninvasive diagnostic examination should be added to the routine test procedures for evaluation and follow-up study of extracranial cerebral vascular disease.

A scanning and transmission electron microscopic study of urinary bladders of mice treated with 2-acetylaminofluorene

Urinary bladders of BALB/c male mice treated with 250 ppm of 2-acetylaminofluorene for 1, 3, 5, 7, and 14 days were examined for early scanning (SEM) and transmission electron microscopic (TEM) changes. SEM observations at days 1, 3, and 5, and TEM observations at days 1 and 3 revealed no significant changes. The bladders of the mice treated for 7 days contained an occasional focus showing irregularity in the shape and size of the superficial cells and SEM revealed ropey microridges in an occasional cell. The bladders of mice treated for 14 days had a greater irregularity of cell size on SEM. TEM changes were evident as early as 5 days with an increase in severity at 7 and 14 days. A numerical reduction of fusiform vesicles, asymmetric membrane plaques and Golgi apparatus along with an increase in membranous whorls, endoplasmic reticulum, cytolysosomes, and small rounded vesicles was evident. The study may aid in a better understanding of early morphologic changes of urothelium in response to a carcinogen.

Comparison of experimental and spontaneous bladder urothelial hyperplasias occurring in BALB/c mice

Spontaneously occurring hyperplasia of urothelium of mice was compared morphologically to hyperplasia induced with 2-acetylaminofluorene (2-AAF) and 4-ethylsulfonylnaphthalene-1-sulfonamide (ENS). Simple and nodular hyperplasias were seen in all groups. Nodular downward hyperplasia was more commonly located in the vertex of the bladder of the 2-AAF treated mice but was more commonly located in the neck region of the ENS and control mice. The 2-AAF induced hyperplasia appeared to be capable of regression or progression to neoplasia. The ENS induced and the spontaneously occurring downward hyperplasia appeared to be secondary to a chronic cystitis and did not appear to progress to neoplasia.

Absorption, metabolism, and excretion of oral testosterone in humans by mass fragmentography

A mass fragmentographic method employing stable isotopically labeled testosterone was employed to follow the time course of urinary excretion of the two main testosterone metabolites, androsterone glucuronide and etiocholanolone glucuronide, in humans after the oral administration of 20 mg testosterone-19.19.19-d3. The results indicate that the extensive metabolism of testosterone in the liver could be the reason that the orally administered testosterone appeared in the circulation only in small amounts, even though testosterone was completely absorbed from the gastrointestinal tract.

Characteristic protein fractions of cerebrospinal fluid disc electrophoretic analysis

The present work was undertaken to determine characteristic proteins of normal cerebrospinal fluid (CSF) by disc electrophoresis in polyacrylamide gel, and to evaluate their usefulness as indicators of blood-brain-CSF barrier disturbance. The technique has been applied to 1280 samples of unconcentrated CSF obtained from 27 reference subjects and 847 neurological patients, with a simultaneous analysis of 361 sera. The pre-albumin content (mean +/- S.D. as a percentage of total protein, 11.0 +/- 2.3%) was higher than formerly reported. One reason for this is that preliminary concentration was not necessary, and the second is related to the principle of protein resolution. The no. 5 protein band of the post-albumin group (3.9 +/- 1.1%) was characteristic, though it has not yet been identified. The no. 3 protein band of the post-transferrin group (5.2 +/- 1.7%) was highly specific to CSF; it was found to be closely related to transferrin, and may correspond to tau fraction obtained by other methods. Barrier dysfunction was easily recognizable by the appearance of polymers of haptoglobin 2-1 or 2-2, because only haptoglobin 1-1 was detected in normal CSF. The percentage of the main region of the G-zone (13.7 +/- 2.6%) was postulated as normal content of CSF immunoglobulins.

Morphologic characteristics of benign and malignant renal cell tumors in control and 2-acetylaminofluorene-treated BALB/c female mice

A total of 108 mice with renal cell tumors were obtained from a total of 25,916 control and 2-AAF-treated BALB/c female mice. A total of 119 renal cell adenomas and 37 renal cell carcinomas from the 108 mice were classified morphologically. The 119 renal cell adenomas were divided into cystic (32%), cystopapillary (29%), papillary (24%), and solid (15%). The 37 renal cell carcinomas were divided into tubolosolid (16%), tubolopapillary (49%) and tubulopleomorphic (35%). Pulmonary metastases occurred only in the tubulopleomorphic adenocarcinomas. In mice having renal cell tumors and surviving less than 650 days, the renal cell carcinomas were usually multiple and renal cell adenomas often coexisted in the same kidney. In mice having renal cell tumors and surviving more than 650 days, the renal cell carcinomas usually consisted of single large tumors without coexisting renal cell adenomas. The results suggest that the renal cell adenoma may progress to renal cell carcinoma. The various dose levels of 2-AAF did not significantly affect the incidence of renal cell tumors.

Immunoglobulins in cerebrospinal fluid--enzyme-immunoassay

Using an enzyme-immunoassay (EIA) technique we established control values for IgA and IgM in cerebrospinal fluid (CSF). These values, together with IgG values determined by single radial immunodiffusion (SRID) technique, showed significant positive correlations with CSF total protein values. The CSF IgA and IgM levels were related to corresponding levels determined in serum. In addition, the values for all 3 immunoglobulin classes in CSF as well as CSF total protein values showed positive correlation with age of subjects, and IgG% and IgA% inreased with age. This new EIA procedure can be completed within 24 h and is sensitive enough for determining all 3 immunoglobulin classes using a small amount (100 microliter or less) of native CSF.

Neovascularization in rats during urinary bladder carcinogenesis induced by N-[4-(5-Nitro-2-furyl)-2-thiazolyl]formamide

Neovascularization in inbred F344 rats during urinary bladder carcinogenesis induced by N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) was examined by scanning electron microscopic observation of vascular casts. FANFT was fed to rats at a level of 0.2% of the diet for 6, 10, or 20 weeks, and vascular casts were examined in these rats at those times and after various times on control diets. Similar foci of vascular proliferation (types I and III) were observed after the use of FANFT as previously reported during bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine. However, the vascular proliferations were observed to regress as the FANFT-induced epithelial proliferations regressed, similar to the observation of reversible hyperplasias induced by cyclophosphamide or ulceration. Type I vascular foci were present after 6 and 10 weeks, but no vascular lesions were seen through week 20 after these groups of rats were fed the control diet for 4 or more weeks. The epithelial lesions present after 6 and 10 weeks of FANFT feeding also regressed and the mucosa returned to normal as observed by light microscopy. Type III foci were present after 12 weeks and were observed through week 20 when epithelial tumors appeared. Rats fed FANFT for 10 weeks and then the control diet developed hyperplastic epithelial lesions and carcinomas by week 52, whereas those fed FANFT for 6 weeks had normal bladders through 52 weeks.

Differentiation between endogenous and exogenous testosterone in human plasma and urine after oral administration of deuterium-labeled testosterone by mass fragmentography

A mass fragmentographic method employing stable isotopically labeled testosterone was employed to simultaneously determine the concentrations of endogenous and exogenous testosterone in the urine and plasma of two healthy male volunteers. After oral administration of 20 mg testosterone-19,19,19-d3, a slight but significant amount of the deuterated testosterone appeared in the plasma and was rapidly cleared. The results show that the exogenous testosterone did not influence the plasma levels or urinary excretion of endogenous testosterone.

Tyrosinemia

A case of tyrosinemia in a three-month-old boy is presented. The patient appeared jaundiced initially with markedly elevated levels of serum tyrosine and a positive Millon-reacting urine. Jaundice persisted and hepatosplenomegaly gradually increased. He died due to liver failure on the 51st day after admission. At autopsy, the liver showed the features of severe giant cell hepatitis including giant cell formation, fibrosis and bile retention. The pancreas and the brain showed characteristic postmortem findings as previously reported in patients with tyrosinemia.

Determination of plasma testosterone by mass fragmentography using testosterone-19-d3 as an internal standard. Comparison with radioimmunoassay

Analytical procedures for the measurement of testosterone by mass fragmentography (MF) using trideuterated testosterone (testosterone-19,19,19-d3) are described. For the calculation of plasma testosterone, peak height ratios were measured by MF performed on the molecular ions of the TFA derivative of testosterone (m/e 480) and testosterone-19,19,19-d3 (m/e 483). The sensitivity of the method was judged from the lower limit of detection of the mass spectrometer which was at 10 pg. For the measurement of the precision, the inter- and intra-assay coefficients of variation (C.V.) were calculated by using a pooled plasma sample; they were 3.15% and 1.79%, respectively. The specificity was investigated by the use of 5 alpha-dihydrotestosterone and the MF method was found to afford a highly selective technique. These results obtained by MF have been compared with the results obtained by a radioimmunoassay method.

Sequential quantitative studies on hyperplastic nodules in the liver of rats treated with carcinogenic chemicals

Sequential quantitative analyses were made of hyperplastic liver nodules induced by treating male Fischer rats first with diethylnitrosamine (DEN) and then with N-(2-fluorenyl)acetamide (2-FAA), alpha-isomer of 1,2-3,4,5,6-hexachlorocyclohexane (alpha-BHC), or phenobarbital. The test rats were injected ip with 200 mg/kg body weight of DEN, given basal diet containing 2-FAA, alpha-BHC, or phenobarbital from week 2 to 12, and subjected to partial hepatectomy at the end of week 3. From week 6, significantly higher percentage areas of hyperplastic nodules per unit area of liver were found in all experimental groups than in the control group. From week 8, significantly more hyperplastic nodules were found in all experimental groups than in the control group. Continuous administration of alpha-BHC or phenobarbital for 12 weeks with partial hepatectomy did not induce hyperplastic nodules. Continuous administration of 2-FAA did induce hyperplastic nodules, but the percentage areas and number of these nodules were significantly lower than in rats injected with DEN and then given 2-FAA orally, with partial hepatectomy.

Cerebral hemodynamics in Shy-Drager syndrome: variability of cerebral blood flow dysautoregulation and the compensatory role of chemical control in dysautoregulation

Cerebrovascular autoregulation and CO2 reactivity were measured repeatedly in 3 patients with the multiple system atrophy type of autonomic insufficiency (Shy-Drager syndrome) by means of the 133Xe injection method. The degree of cerebral blood flow (CBF) dysautoregulation showed day-to-day variations in 2 of the 3 patients. The CO2 reactivity was normal or supernormal in the supine position in patients with impaired autoregulation. In the head-up position the response to CO2 was slightly suppressed in 2 of the patients, suggesting that chemical control may have tended to compensate for CBF dysautoregulation. It is concluded that the mechanism of chemical control of the cerebrovasculature is different from that which controls autoregulation and may have partially compensated for CBF dysautoregulation.

Effects of cholinesterase inhibitors on the spasmogenic action of acetate esters on rat uterus

Acetate esters, such as phenyl acetate and aspirin, induced atropine-sensitive contractions of isolated uterus only when choline was present. These contractions were selectively and reversibly inhibited by carbamate-type cholinesterase inhibitors, such as neostigmine and eserine, and quaternary ammonium compounds, such as tetraethylammonium and decamethonium. After treatment with organophosphorus cholinesterase inhibitors, such as di-isopropyl fluorophosphate and tetraethyl pyrophosphate, the uterus failed to respond to the acetate esters, even when high concentrations of choline were present. The inhibition of the response of the uterus by organophosphates was effectively removed by pyridine-2-aldoxime methiodide. Pretreatment of the uterus with neostigmine or simultaneous addition of high concentrations of quaternary ammonium compounds prevented the inhibition by organophosphates. The inhibition produced by neostigmine was also reduced by simultaneous addition of quaternary ammonium compounds. These findings suggest that some esterase having an anionic site and an esteratic site, probably cholinesterase, may mediate in the uterine contractions induced by acetate esters in the presence of choline, and that inhibition by organophosphates, carbamates and quaternary ammonium compounds of cholinesterase activity in the preparation may impede the initiation of contractions by the acetate esters in the presence of choline.

Effect of various factors on the induction of liver tumors in animals by quinoline

Tumorigenic effect of a diet containing quinoline on the liver of various animals and the synergistic or antagonistic effect by other chemicals on quinoline hepatocarcinogenesis in rats were examined. It was concluded that 4,4'-diaminodiphenylmethane (0.1%) and 3-methylcholanthrene (0.0067%) had a significant inhibitory effect on liver carcinogenesis due to quinoline in rats, but 1-naphthyl isothiocyanate (0.06%) and p-hydroxypropiophenone (1.0%) had no inhibitory effect in the present observations. Transmission electron-microscopic study demonstrated the fine structure of vascular tumors induced by quinoline. On the other hand, it was found that quinoline induced liver tumors in both sexes of mice and rats but not in hamsters or guinea pigs. Male rats were more susceptible than females to the tumorigenic action of quinoline, and mice showed the least susceptibility. Histological changes in the liver of rats or mice induced by quinoline were clasified as hemangioendotheliomas or hemangiosarcomas and hepatocellular carcinomas. Several rats treated with quinoline had hemangiosarcomatous metastatic foci in the lung.

Effect of N-(3,5-dichlorophenyl)succinimide on the histological pattern and incidence of kidney tumors induced by streptozotocin rats

The effect of the nephrotoxic substance, N-(3,5-dichlorophenyl)succinimide, on the histological pattern and incidence of kidney tumors induced by streptozotocin in rats was studied. In groups administered streptozotocin alone or in combination with nicotinamide, the histological pattern and the incidence of kidney tumors in rats were similar; renal cell tumors developed in 1 of 9 rats (11.1%) and in 2 of 17 rats (11.8%), respectively. However, post-treatment with N-(3,5-dichlorophenyl)succinimide increased the induction of epithelial tumors by streptozotocin, and embryonal cell tumors were also induced nearly as frequently. Administration of nicotinamide alone did not result in the development of kidney tumors.

Isolation and biological characterization of a measles virus-like agent from the brain of an autopsied case of subacute sclerosing panencephalitis (SSPE)

Isolation of a cytopathic agent causing formation of syncytial giant cells in co-cultivated Vero cells from the brain of an autopsied case of subacute sclerosing panencephalitis (SSPE) is reported. The syncytia usually autolyzed from the center after growing to 1 to 2 mm in diameter and then detached from the culture vessels, and finally made macroscopically recognizable round plaques on the monolayer under liquid overlay. The agent was identified serologically as an agent related to measles virus, by both immunofluorescent tests and plaque reduction tests using anti-measles sera. However, the infected cells did not produce either virions or hemagglutinin, and failed to show hemadsorption and hemolysis of African green monkey red cells even after the 55th passage through Vero cells. Newborn mice, adult mice and hamsters showed neurologic signs after intracerebral inoculations of the infected cells, and most of them died from acute encephalitis. Guinea pigs were unsusceptible. From the brain of the animals with neurologic signs, a similar agent to the inoculated one was recovered. The new isolate appears to be a strain closely related to measles virus on the basis of serology, and was designated as SSPE-"Kitaken-1" strain.

Toxic neuropathy as a complication of thiophenicol therapy

Two cases with sensory neuropathy due to thiophenicol therapy are reported. Thiophenicol neuropathy is hitherto unreported in literature published in English. Neurological manifestations of these cases were similar to those of chloramphenicol neuropathy, but rather marked impairment of position sense in the lower extremities was characteristic. Thiophenicol neuropathy reported in Japanese literature was reviewed and it is concluded that thiophenicol administered in large doses (70-150 g) or for long periods (more than 3-5 months) appeared to have a toxic effect on the nervous system.

Combination effect of citrinin and other chemicals on rat kidney tumorigenesis

Histological studies were made on the nephrotoxic effect of citrinin on the kidneys of rats, with or without previous treatment with the nephrotoxic chemicals, N-(3,5-dichlorophenyl)succinimide (NDPS) and N-nitrosodimethylamine (DMN). Oral administration of 0.02% or 0.05% citrinin alone caused signs of kidney injury but did not induce kidney tumors. On treatment with DMN alone, 8 of 14 rats (57.1%) developed kidney tumors; two (14.3%) were renal cell tumors, eight (57.1%) embryonal cell tumors, and one (7.1%) hemangioendothelioma. On the other hand, kidney tumors developed in 18 of 19 rats (94.7%) and 13 of 15 rats (86.7%) by the administration of 0.02% and 0.05% citrinin, respectively, after DMN. The tumors in these two groups were diagnosed histologically as renal cell tumors in 18 (94.7%) in group IV and 13 (86.7%) in group III, and as embryonal cell tumors in 14 (73.7%) in group IV and 9 (60.0%) in group III. Thus, in groups treated with citrinin after DMN the incidence of renal cell tumors was much greater and the incidence of embryonal cell tumors slightly greater than in the group treated with DMN alone. Kidney tumors developed in 4 of 18 rats (22.2%) treated with 0.02% citrinin after NDPS, but treatment with NDPS alone did not induce kidney tumors. Thus, treatment with citrinin changes the histological type and incidence of kidney tumors in rats induced by DMN. Moreover, this study confirms that citrinin in combination with NDPS can induce kidney tumor in rats, which was renal cell tumor (adenoma) histologically.

Carcinogenic activity of quinoline on rat liver

The effects of prolonged p.o. administration of quinoline or 2-chloroquinoline on rat liver were examined histologically. Hepatocellular carcinomas and hemangioendotheliomas were observed in the livers of rats fed a basal diet containing 0.05, 0.10, or 0.25% quinoline for about 16 to 40 weeks. However, no neoplastic changes were seen in the livers of rats fed a basal diet containing 0.05, 0.10, or 0.25% 2-chloroquinoline for 40 weeks. In groups that received low concentrations of quinoline, the incidences of hepatocellular carcinomas were higher and the incidences of hemangioendotheliomas were lower than in the group that received a high concentretion of quinoline. The liver tumors induced by quinoline were classified histologically as hemangioendotheliomas or hemangiosarcomas and trabecular hepatocellular carcinomas. Typical nodular hyperplasias were occasionally seen in the livers of rats treated with quinoline. 2-Chloroquinoline did not induce any nodular hyperplasia or other neoplastic changes, but it caused diffuse fatty changes of parenchymal cells. Oval cell infiltration and bile duct proliferation were slight or moderate. Cirrhotic changes were rare in the livers of rats treated with either quinoline or 2-chloroquinoline. The serum levels of glutamic oxaloacetic transaminase and alkaline phosphatase were slightly changed in groups treated with quinoline, but no other remarkable changes were detected.

Efferent projection of the nucleus praeopticus medialis to the median eminence in rats

Efferent projection from the medial preoptic nucleus, especially to the median eminence, was studied in the rat by light and electron microscopy, in combination with 3H-leucine labelling and electrical coagulation of the nucleus. In the light microscopy autoradiographs of the brain, an ipsilateral distribution of silver grains was followed caudally and dorsally in the periventricular area, into the triangular area between the ventromedial nucleus and the arcuate nucleus, and, further, into the paraventricular and supraoptic nuclei and median eminence. After electrical coagulation of the medial preoptic area, electron microscopy showed numerous degenerated nerve terminals in the external layer of the median eminence. Occasionally, cored vesicles (90 nm mean diameter with a core of 70 nm mean diameter) and clear vesicles (40-50 nm diameter) were encountered in the axoplasm of the degenerated nerve terminals. These findings indicate that the axons of the nerve cells of the medial preoptic nucleus extend caudally, terminating in the external layer of the median eminence.

Pathologic analysis of chemical nephritis in rats induced by N-(3,5-dichlorophenyl)succinimide

The effects of N-(3,5-dichlorophenyl)succinimide (NDPS) administration to rats were studied by blood chemical, histopathologic, histochemical, and ultrastructural examinations. Administration of 5000 p.p.m. of NDPS induced severe damage of the kidneys, but did not affect other organs. Administration of 2500 p.p.m. of NDPS had little effect, even on the kidneys. Chemical analysis of the blood showed that the urea nitrogen level increased with the increase in the period of NDPS administration. Histopathologic examination showed intensive cell infiltration, mainly of lymphocytes, into the renal interstitium after NDPS administration for only 4 weeks. After NDPS administration for 12 weeks or more, typical interstitial nephritis was observed. Histochemical analysis showed that after only 1 week various enzymatic activities in the proximal convoluted tubules were markedly decreased whereas their activities in the distal convoluted tubules were relatively well preserved for at least 4 weeks. These results indicate that NDPS predominantly attacked the proximal convoluted tubules. After 4 weeks, the most prominent ultrastructural changes were seen in the proximal convoluted tubules where the epithelial cells lost their polarity and had a very abnormal arrangement. These cells showed well developed, edematous microvilli, poorly developed basal infoldings, swollen mitochondria of various sizes, aggregated beta-type glycogen granules, and debris of erythrocytes. Development of the endoplasmic reticulum, Golgi complex, ribosomes, and lysosomes was poor in the cytoplasm. These investigations indicate that NDPS affects the function of the proximal convoluted tubules. NDPS is a selective nephrotoxic substance. That is, it initially damages the proximal convoluted tubules, and subsequently causes interstitial nephritis. It is suggested that nephritis induced by NDPS is useful as a model of interstitial nephritis in man.