[A case of cerebral venous thrombosis with reversible brain parenchymal lesions: usefulness of diffusion weighted imaging and measurement of apparent diffusion coefficient]

A 47-year-old man with a history of thrombophlebitis of his left leg for several years presented with a mild left hemiparesis and ipsilateral hypesthesia. Magnetic resonance imaging showed subacute thrombosis of the superior sagittal sinus and a cortical vein of the right cerebral hemisphere. A linear hyperintense area was found in the white matter of the right postcentral gyrus on T 2- and diffusion weighted axial imagings on the 7 days after the onset. The patient was treated conservatively, and his clinical course was uneventful. His neurological dysfunctions recovered within approximately three weeks after the onset. The white matter lesion in the right postcentral gyrus also disappeared one month later. The apparent diffusion coefficients (ADCs) in the white matter of the pre- and postcentral gyrus were measured bilaterally on the ADC mapping imaging. In the subacute stage, the ADC values in the white matter of the right pre- and postcentral gyrus were 0.50 x 10(-3) mm2/sec and 0.91 x 10(-3) mm2/sec, respectively. The %ADC indicating the ratio of ADC value of the lesion to that of the contralateral brain tissue was calculated. The %ADCs in the white matter of the pre- and postcentral gyrus were 64.9% and 124.5% respectively. In the chronic stage, the ADC values in the white matter of the right pre- and postcentral gyrus were 0.96 x 10(-3) mm2/sec and 0.99 x 10(-3) mm2/sec, and the %ADCs improved to 106.7% and 106.5% respectively. The lesions in the white matter of the right pre- and postcentral gyrus were reversible. The former was thought to be mainly ascribed to cellular edema and the latter was vasogenic edema. The present case showed when %ADC of the ischemic lesion in cerebral venous thrombosis was higher than 60%-70%, conservative therapy alone is sufficient effective for the improvement of neurological deficits.

Successful treatment of a ruptured enlarged infundibular widening of the posterior communicating artery--case report

A 67-year-old female with a history of hypertension and cerebral infarction presented with subarachnoid hemorrhage (SAH) (Hunt and Kosnik grade 4). Brain computed tomography (CT) revealed a clot dominantly on the right (Fisher's classification Group 4). Cerebral angiography showed funnel-shaped widenings at the origins of the bilateral posterior communicating arteries. The maximum diameter of the widening was greater than 3 mm, so this widening was called an enlarged infundibular widening. Angiography showed a small bulge protruding posterolaterally from the wall of the right enlarged infundibular widening, and the right posterior communicating artery arose from the apex of the enlarged infundibular widening. Based on the findings of the brain CT and cerebral angiography, the diagnosis was SAH due to rupture of the right enlarged infundibular widening. Approximately 12 hours after the onset, the clot was evacuated through the right pterional approach. Bleeding from the small bulge of the right enlarged infundibular widening occurred intraoperatively, so a right-angled ring clip was applied parallel to the right internal carotid artery to obliterate the rupture point. Postoperatively, she was discharged without neurological deficit, and follow-up CT showed no other new infarction. We recommend clipping rather than wrapping or coating for similar cases of ruptured enlarged infundibular widening.

Synthesis of all four possible stereoisomers of 5,9-dimethylpentadecane, the major sex pheromone component of the coffee leaf miner moth, Perileucoptera coffeella

All of the four possible stereoisomers of 5,9-dimethylpentadecane, the major sex pheromone component of the coffee leaf miner moth (Perileucoptera coffeella), were synthesized by using the methyl esters of (S)- and (R)-3-hydroxy-2-methylpropanoic acid as chiral sources for the purpose of determining the stereochemistry of the pheromone.

Seasonal changes in the hypothalamo-pituitary-testes axis of the Japanese wood mouse (Apodemus speciosus)

Seasonal changes in the hypothalamo-pituitary-testes axis of the Japanese wood mice (Apodemus speciosus) were studied. The testes, epididymis, pituitary and hypothalamus were compared between mice in the breeding season (July) and non-breeding season (October) using morphological techniques, and the plasma testosterone level was evaluated by enzyme immunoassay. Significant differences in these tissues were observed between the breeding season and the non-breeding season. Specifically, differences in the non-breeding season included 1) a decline in testicular and epididymal weights, arrest of spermatogenesis and decrease of serum testosterone concentration; 2) a decrease in the number of luteinizing hormone (LH)-, follicle stimulating hormone (FSH)-, prolactin (PRL)-, and growth hormone (GH)-immunoreactive cells, and decrease in the size of FSH, PRL, and GH-immunoreactive cells; and 3) an increase in the size of gonadotropin-releasing hormone (GnRH)-immunoreactive neurons. Our findings indicate that the male adult Japanese wood mouse exhibits unique seasonal changes in the hypothalamo-pituitary-testes axis which are not found in laboratory mice.

Superior sagittal sinus and cerebral cortical venous thrombosis caused by congenital protein C deficiency--case report

A 47-year-old male receiving anticoagulant therapy for thrombophlebitis in the left leg for several years presented with mild left hemiparesis and ipsilateral hypesthesia. The cause of the thrombophlebitis was still unknown. Magnetic resonance (MR) imaging showed subacute thrombosis of both the superior sagittal sinus (SSS) and a cortical vein in the right cerebral hemisphere. Fluid attenuation inversion recovery axial MR imaging demonstrated these lesions more obviously than conventional T2-weighted axial MR imaging. Right carotid angiography showed a partial SSS filling defect and occlusion of the cortical vein with collateral circulation. Coagulation studies revealed decreases in both protein C activity and antigen levels with normal levels of blood coagulation factors II, VII, IX, and X and protein S activity and antigen. The patient's mother had normal levels of both protein C activity and antigen, but his father had decreased levels. The diagnosis was SSS and cerebral cortical venous thrombosis caused by congenital protein C deficiency. The patient was treated conservatively, and his clinical course was uneventful. His neurological dysfunctions recovered within approximately 3 weeks after the onset. Ten months later, right carotid angiography showed recanalization of the SSS and partial filling of the cortical vein. Anticoagulant therapy has been continued, and no cerebral venous thrombosis has recurred during the 1.5 years after the onset.

Simple synthesis of 5,9-dimethylated long-chain alkanes, the sex pheromones of leaf miner moths

Each stereoisomeric mixture of 5,9-dimethylpentadecane and 5,9-dimethylhexadecane, the major and the minor sex pheromone components of Perileucoptera coffeella, respectively, was synthesized in about 25% overall yield through 6 steps from beta-citronellol. 5,9-Dimethylheptadecane, the major sex pheromone component of Leucoptera malifoliella, was also synthesized analogously as a stereoisomeric mixture in a 22% overall yield.

Inhibitory effect of citrus nobiletin on phorbol ester-induced skin inflammation, oxidative stress, and tumor promotion in mice

The intake of citrus fruits has been suggested as a way to prevent the development of some types of human cancer. Nitric oxide (NO) is closely associated with the processes of epithelial carcinogenesis. We attempted a search for NO generation inhibitors in Citrus unshiu. The active constituent was traced by an activity-guiding separation. NO and superoxide (O2-) generation was induced by a combination of lipopolysaccharide and IFN-gamma in mouse macrophage RAW 264.7 cells, and by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocyte HL-60, respectively. Expression of inducible NO synthase and cyclooxygenase 2 proteins were detected by Western blotting. The in vivo anti-inflammatory and antitumor promoting activities were evaluated by topical TPA application to ICR mouse skin with measurement of edema formation, epidermal thickness, leukocyte infiltration, hydrogen peroxide production, and the rate of proliferating cell nuclear antigen-stained cells. As a result, nobiletin, a polymethoxyflavonoid, was identified as an inhibitor of both NO and O2- generation. Nobiletin significantly inhibited two distinct stages of skin inflammation induced by double TPA application [first stage priming (leukocyte infiltration) and second stage activation (oxidative insult by leukocytes)] by decreasing the inflammatory parameters. It also suppressed the expression of cyclooxygenase-2 and inducible NO synthase proteins and prostaglandin E2 release. Nobiletin inhibited dimethylbenz[a]anthracene (0.19 micromol)/TPA (1.6 nmol)-induced skin tumor formation at doses of 160 and 320 nmol by reducing the number of tumors per mouse by 61.2% (P < 0.001) and 75.7% (P < 0.001), respectively. The present study suggests that nobiletin is a functionally novel and possible chemopreventive agent in inflammation-associated tumorigenesis.

Relationship between gingival health and dental caries in children aged 7-12 years

The purpose of this study was to investigate the relationship between gingival health and dental caries in elementary school children in Japan. The subjects were 474 children aged 7 to 12 years who attended dental check-ups at an elementary school. The Oral Rating Index for Children, which consists of five categories (+2, +1, 0, -1, -2), was used to rate the findings of the gingival health examination. The dental examination was performed using the WHO caries diagnostic criteria for DMFT. Children were divided into three groups: a healthier group (H-group) made up of those scoring +2 (excellent) or +1 (good), an equivocal group (E-group) made up of those scoring 0, and a gingival less-healthy group (L-group) made up of those scoring -2 (very poor) or -1 (poor). Overall percentages for the H-group, E-group and L-group were 48.3%, 21.5% and 30.2%, respectively. The number in the L-group increased with increasing age. The mean scores of the DT and DMFT in the H-group were significantly lower than those in the L-group (p < 0.01 and p < 0.05, respectively). The results suggest that oral hygiene instruction should be given to children in order to motivate self-care, not only to avoid dental caries but also to prevent gingivitis.

[Intracranial vertebral artery stenosis successfully revascularised by cerebral angioplasty and stenting in chronic stage: a case report of prompt improvement of the neurological impairment]

A 72-year-old man with a history of hypertension had a left cerebellar infarction and followed by a right cerebellar infarction within about one and a half months after the initial stroke. Brain magnetic resonance images(MRI) showed infarctions in both middle cerebellar peduncles and in the mid-portion of lower pons. Right veretebral artery(VA) terminated in posterior inferior cerebellar artery(PICA). Left intracranial VA has a high-grade eccentric atherosclerotic stenosis(91%) proximal to the left PICA. No collateral circulation was developed from bilateral carotid arteries. Three months after the final ischemic episode, the patient had remained bed ridden and needed a whole assistance for regular daily life because of severe ataxia of four limbs and truncs and of left hemiparesis. The patient and his family gave us informed written consent, then cerebral angioplasty and stenting(CAS) was performed for the left VA stenosis, which was sufficiently dilated. Iodine-123 iodoamphetamine(123I-IMP) single photo emission computed tomography (SPECT) showed hypoperfusion in both cerebellar hemispheres before CAS. Post CAS 123I-IMP SPECT scans demonstrated improvement of the hypoperfusion in the left cerebellar hemisphere. Ataxia of four limbs, left hemiparesis and his will for physical therapy improved in a short period after the treatment. Ten months later, the left VA had a mild stenosis and patient presented mild truncal ataxia and needed less assistance for regular daily life. The present case indicated that improvement of neurological impairment was expected by the endovascular revascularization even in a chronic stage.

Efficacy of FK463, a new lipopeptide antifungal agent, in mouse models of disseminated candidiasis and aspergillosis

The efficacy of intravenous injection of FK463, a novel water-soluble lipopeptide, was evaluated in mouse models of disseminated candidiasis and aspergillosis and was compared with those of fluconazole (FLCZ) and amphotericin B (AMPH-B). In the candidiasis model, FK463 significantly prolonged the survival of intravenously infected mice at doses of 0.125 mg/kg of body weight or higher. In disseminated candidiasis caused by Candida species, including FLCZ-resistant Candida albicans, FK463 exhibited an efficacy 1.4 to 18 times inferior to that of AMPH-B, with 50% effective doses (ED(50)s) ranging from 0.21 to 1.00 mg/kg and 0.06 to 0.26 mg/kg, respectively, and was much more active than FLCZ. The protective effect of FK463 was not obviously influenced by the fungal inoculum size, the starting time of the treatment, or the immunosuppressed status of the host. The reduction in efficacy was less than that observed with FLCZ or AMPH-B. The efficacy of FK463 was also evaluated in the disseminated candidiasis target organ assay and was compared with those of FLCZ and AMPH-B. Efficacies were evaluated on the basis of a comparison between the mean log(10) CFU in kidneys in the groups treated with antifungal agents and that in control group. A single dose of FK463 at 0.5 mg/kg or higher significantly reduced the viable counts in kidneys compared with the numbers of yeast cells before treatment, and its efficacy was comparable to that of AMPH-B, while FLCZ at 4 mg/kg showed only a suppressive effect on the growth of C. albicans in the kidneys. In the disseminated aspergillosis model, FK463 given at doses of 0.5 mg/kg or higher significantly prolonged the survival of mice infected intravenously with Aspergillus fumigatus conidia. The efficacy of FK463 was about 2 times inferior to that of AMPH-B, with ED(50)s ranging from 0.25 to 0.50 mg/kg and 0.11 to 0.29 mg/kg, respectively. These results indicate that FK463 may be a potent parenterally administered therapeutic agent for disseminated candidiasis and aspergillosis.

Preparation of (-)-periplanone D and its physical and spectroscopic properties

(-)-Periplanones C and D were obtained in reproducible yields by modifying reported procedures. Our synthetic sample of (-)-periplanone D showed somewhat different physical and spectroscopic properties from those reported in the literature.

Efficacy of FK463, a new lipopeptide antifungal agent, in mouse models of pulmonary aspergillosis

The efficacy of FK463, a novel water-soluble lipopeptide, was evaluated in mouse models of pulmonary aspergillosis and was compared with that of amphotericin B (AMPH-B). In the pulmonary aspergillosis models induced by intranasal inoculation, FK463 exhibited good efficacy, with 50% effective doses in the range of 0. 26 to 0.51 mg/kg of body weight; these values were comparable to those of AMPH-B. In an Aspergillus target organ assay with immunosuppressed mice, under conditions of constant plasma levels of FK463, using a subcutaneously implanted osmotic pressure pump, a significant reduction in viable fungal cells was observed at plasma FK463 levels of 0.55 to 0.80 microgram/ml or higher. We conclude that FK463 is highly effective in the treatment of pulmonary aspergillosis in this animal model. These results indicate that FK463 may be a potent parenterally administered antifungal agent for pulmonary aspergillosis.

[A case of cerebellar meningo-encephalitis caused by Epstein-Barr virus(EBV): usefulness of Gd-enhanced MRI for detection of the lesions]

We report a patient with cerebellar meningo-encephalitis by Epstein-Barr virus(EBV) in which the responsible lesions were detected by Gd-enhanced MRI. A 61-year-old woman with a history of liver cirrhosis and diabetes mellitus presented with cerebellar signs such as ataxia of the trunk, bilateral upper and lower extremities and slurred speech two weeks after the acute upper respiratory inflammation for several days. Serum IgM antibody(Ab) to EBV viral capsid antigen(VCA) was 1:10, Ab to EBV(VCA) IgG was 1:1280, Ab to early antigen diffuse and restricted (EADR) IgG was 1:40, Ab to EBV nuclear antigen (EBNA) was 1:80. Other viral antibody titers were not elevated significantly in serum. Cerebrospinal fluid (CSF) pressure was 195 mmH2O, containing 464 cells/mm3, protein 68 mg/dl and glucose 43 mg/dl. Only CFS Ab to EBV(VCA) IgG elevated significantly (1:16). In acute phase plain MRI was normal except for swelling of the cerebellar hemispheres while Gd-enhanced MRI showed a leptomeningeal enhancement of bilateral cerebellar hemispheres and of vermis disappeared within one month. A homogeneously enhanced lesion in the left dentate nucleus appeared one month after the onset of illness. This lesion had been detected on Gd-enhanced MRI for three months after clinical symptoms were improved. No abnormal finding was shown in the supratentorial region during the whole clinical course. In the literature, EBV encephalitis has a wide range of MR findings which may vary in a short period. We emphasize that frequent MR examinations including Gd-enhanced MRI is useful to evaluate inflammatory or demyelinating diseases in the posterior fossa.

In vitro activities of a new lipopeptide antifungal agent, FK463, against a variety of clinically important fungi

The in vitro antifungal activity and spectrum of FK463 were compared with those of amphotericin B, fluconazole, and itraconazole by using a broth microdilution method specified by National Committee for Clinical Laboratory Standards document M27-A (National Committee for Clinical Laboratory Standards, Wayne, Pa., 1997). FK463 exhibited broad-spectrum activity against clinically important pathogens including Candida species (MIC range, <==0.0039 to 2 microg/ml) and Aspergillus species (MIC range, <==0.0039 to 0.0313 microg/ml), and its MICs for such fungi were lower than those of the other antifungal agents tested. FK463 was also potently active against azole-resistant Candida albicans as well as azole-susceptible strains, and there was no cross-resistance with azoles. FK463 showed fungicidal activity against C. albicans, i.e., a 99% reduction in viability after a 24-h exposure at concentrations above 0.0156 microg/ml. The minimum fungicidal concentration (MFC) assays indicated that FK463 was fungicidal against most isolates of Candida species. In contrast, the MFCs of FK463 for A. fumigatus isolates were much higher than the MICs, indicating that its action is fungistatic against this species. FK463 had no activity against Cryptococcus neoformans, Trichosporon species, or Fusarium solani. Neither the test medium (kind and pH) nor the inoculum size greatly affected the MICs of FK463, while the addition of 4% human serum albumin increased the MICs for Candida species and A. fumigatus more than 32 times. Results from preclinical in vitro evaluations performed thus far indicate that FK463 should be a potent parenteral antifungal agent.

Syntheses and evaluation of amidinobenzofuran derivatives as tryptase inhibitors

We report the syntheses and evaluation of amidinobenzofuran derivatives as tryptase inhibitors. Among the compounds we evaluated, 1,5-Bis[4-(5-amidinobenzofuran-2-ylcarbonyl)piperazinylca rbonylmethoxy]cyclooctane 26 (AY0068) was found to be a selective and potent non-peptide inhibitor. 26 was effective in PCA reaction in rats without showing antihistaminic activity.

In vitro antibacterial activity of FK041, a new orally active cephalosporin

The in vitro activity of FK041, a new orally active cephem antibiotic, against a wide variety of clinical isolates of bacteria was investigated and compared with those of cefdinir (CFDN) and cefditoren (CDTR). FK041 exhibited broad spectrum activity against reference strains of Gram-positive and Gram-negative aerobes and anaerobes. FK041 was active against clinical isolates of Gram-positive organisms except Enterococcus faecalis with MIC90s less than 1.56 microg/ml. FK041 was more active than CFDN and CDTR against Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae and was comparable to CFDN and CDTR against Streptococcus pyogenes and Streptococcus pneumoniae. FK041 had no activity against methicillin-resistant staphylococci, like CFDN and CDTR. FK041 showed moderate activity against penicillin-resistant S. pneumoniae with an MIC range of 0.05 approximately 3.13 microg/ml, and was superior to CFDN but inferior to CDTR. Against clinical isolates of many Gram-negative organisms such as Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, FK041 had good activity comparable or superior to those of CFDN and CDTR. However, it was inferior to CDTR in activity against Moraxella catarrhalis, Haemophilus influenzae, Morganella morganii, and Serratia marcescens, and was inactive against Pseudomonas aeruginosa. With FK041 a small difference between MIC and MBC against S. aureus, E. coli, K. pneumoniae, and H. influenzae was found, indicating that its action is bactericidal against these species. FK041 was stable to group 2beta-lactamase hydrolysis but was unstable to group 1beta-lactamase hydrolysis. The stability of FK041 to these enzymes was similar to those of CFDN and CDTR. FK041 showed high affinity for the main penicillin-binding proteins (PBPs) of S. aureus (PBP 3, 2, and 1) and E. coli (PBP 3, 4, lbs, 2, and 1a).

In vivo antibacterial activity of FK041, a new orally active cephalosporin

The therapeutic activities of orally administered FK041 were evaluated in mouse models of systemic and local infections with a variety of bacteria and were compared with those of cefdinir (CFDN) and cefditoren pivoxil (CDTR-PI). FK041 exhibited potent therapeutic activity against lethal systemic infections induced by intraperitoneally inoculated Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae with 50% effective doses (ED50) in the range of 0.20 to 0.36 mg/kg and was more active than CFDN and CDTR-PI. This result correlated well with its in vitro activity. The therapeutic effects of FK041 and reference drugs on murine local infections were evaluated in an in vivo pharmacokinetic model simulating human plasma concentrations for oral administration of 50 mg, 100 mg, and 200 mg. Against murine subcutaneous abscess induced by S. aureus, FK041 was as effective as CFDN and significantly more effective than CDTR-PI in reducing the number of recoverable viable bacteria in the skin at the infection sites. The efficacy of FK041 against murine pneumonia with H. influenzae was comparable to that of CDTR-PI and was superior to that of CFDN in reducing viable bacteria activity in the lungs. These results strongly suggest that FK041 has potential for clinical use against various bacterial infections.

Intrafamilial distribution of mutans streptococci in Japanese families and possibility of father-to-child transmission

The purpose of this study was to investigate the intrafamilial distribution of mutans streptococci in Japanese families using chromosomal DNA fingerprinting with three endonucleases; EcoRI, HindIII and HaeIII. The analysis of 1,908 isolates cultured from the dental plaque of 76 subjects from 20 families (20 married couples and 36 of their children) resulted in the identification of 144 genotypes containing 114 strains of Streptococcus mutans (serotype c, 66.7%; e, 12.5%) and 30 strains of S. sobrinus (d, 13.2%; g, 7.6%). A mean of 1.89 genotypes (from one to four) was harbored in individual subjects, and a mean of 4.10 genotypes from two to seven was harbored in individual families. Among the 70 genotypes found in the children, 36 (51.4%) were in agreement with their mothers and 22 (31.4%) were in agreement with their fathers. The other genotypes (18.6%) did not correspond with the parents. Homologous strains between parents were found in only two couples. This result showed that fathers or others as well as mothers can be sources of transmission. Further, the serotype d, e and g strains showed significantly higher probabilities of transmission than serotype c.

Partial inhibition of Na,K-ATPase activity in cultured rabbit non-pigmented ciliary epithelium following an episode of cytoplasmic ATP depletion

Ouabain-sensitive ATP hydrolysis (Na,K-ATPase activity) was measured in digitonin-permeabilized monolayers of cultured cells derived from rabbit non-pigmented ciliary epithelium. Diminished Na,K-ATPase activity was observed in cells that had been pre-treated 10 min with the protein kinase C activator, PDBu, as well as in cells that had been cooled to 4 degrees C for 4 h then rewarmed to 37 degrees C for 30 min (cool-rewarm manoeuvre). In the intact cells, ouabain binding was not decreased either by PDBu treatment or the cool-rewarm manoeuvre. However, both PDBu and the cool-rewarm manoeuvre increased the rate of ouabain-sensitive potassium (86Rb) uptake measured in intact cells. Cell ATP content was diminished in PDBu-treated cells and cells subjected to the cool-rewarm manoeuvre. We suggest that an episode of ATP depletion might initiate a mechanism which causes lasting, partial inhibition of Na,K-ATPase activity. In keeping with this suggestion, diminished Na,K-ATPase activity was observed in cells that had been pre-treated 20 min with the metabolic inhibitors CCCP or rotenone and in cells pre-treated 2.5 h in dextrose-free medium. This study illustrates that Na,K-ATPase activity measured in the permeabilized cell is a complex parameter which is not necessarily a reliable indicator of sodium pump responses in the intact cell.

The effect of increasing gastric pH upon the bioavailability of orally-administered foscarnet

For systemic use, the anti-cytomegalovirus (CMV) agent foscarnet must be given intravenously because oral administration results in unmeasurable or barely measurable plasma levels. At low pH, foscarnet decomposes via an acid-catalyzed decarboxylation; therefore, poor oral bioavailability might be due to decomposition of foscarnet in gastric acid. We evaluated whether increasing gastric pH with ranitidine would enhance the absorption of oral foscarnet in six asymptomatic HIV-infected individuals. Each volunteer received two oral 4000-mg (60 mg/kg) doses of foscarnet, preceded intravenously by a 20-min infusion of either ranitidine 50 mg in D5W or D5W alone in a randomized, double-blind, cross-over study. Intragastric pH monitoring revealed that subjects had evidence of gastric acid production (pH < 2.0) prior to administration of ranitidine and increased gastric pH (pH > 6.0) following ranitidine administration. Most foscarnet plasma levels were below the assay limit of detection (33 microM) with only 4/30 levels detectable after D5W and 8/30 after ranitidine. Urinary recovery of foscarnet increased after ranitidine pretreatment. A mean recovery of 9.9% of the drug was realized in the urine in 24 h following ranitidine pretreatment compared to 6.2% of the dose after D5W pretreatment (P < 0.03). We estimate that 9.9% recovery in the urine in 24 h is equivalent to absorption of 17.1% of the oral dose. In spite of the enhanced bioavailability associated with ranitidine pretreatment, the degree of absorption is still insufficient to achieve effective plasma concentrations for the treatment of CMV or acyclovir-resistant herpes viruses. We conclude that gastric acidity is a determinant of foscarnet absorption, albeit not a major one. Oral foscarnet is unlikely to be clinically useful even if administered in the setting of increased gastric pH.